Coagulation factor IX
PDB rendering based on 1pfx.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 1CFH, 1CFI, 1EDM, 1IXA, 1MGX, 1NL0, 1RFN, 2WPH, 2WPI, 2WPJ, 2WPK, 2WPL, 2WPM, 3KCG, 3LC3, 3LC5
Identifiers
Symbols	F9; FIX; HEMB; P19; PTC; THPH8
External IDs	OMIM: 300746 MGI: 88384 HomoloGene: 106 ChEMBL: 2016 GeneCards: F9 Gene
EC number	3.4.21.22
Gene Ontology Molecular function • serine-type endopeptidase activity • calcium ion binding • peptidase activity Cellular component • extracellular region • extracellular region • endoplasmic reticulum lumen • Golgi lumen • plasma membrane Biological process • proteolysis • blood coagulation • blood coagulation, intrinsic pathway • blood coagulation, extrinsic pathway • peptidyl-glutamic acid carboxylation • post-translational protein modification • cellular protein metabolic process Sources: Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	2158	14071
Ensembl	ENSG00000101981	ENSMUSG00000031138
UniProt	P00740	P16294
RefSeq (mRNA)	NM_000133.3	NM_007979.1
RefSeq (protein)	NP_000124.1	NP_032005.1
Location (UCSC)	Chr X: 138.61 – 138.65 Mb	Chr X: 57.25 – 57.28 Mb
PubMed search	[1]	[2]
This box: view talk edit

Factor IX (or Christmas factor) (EC 3.4.21.22) is one of the serine proteases of the coagulation system; it belongs to peptidase family S1. Deficiency of this protein causes hemophilia B. It was discovered in 1952 after a young boy named Stephen Christmas was found to be lacking this exact factor, leading to hemophilia.^[1].

Physiology[link]

The blood coagulation and Protein C pathway.

Factor IX is produced as a zymogen, an inactive precursor. It is processed to remove the signal peptide, glycosylated and then cleaved by factor XIa (of the contact pathway) or factor VIIa (of the tissue factor pathway) to produce a two-chain form where the chains are linked by a disulfide bridge.^[2][3] When activated into factor IXa, in the presence of Ca²⁺, membrane phospholipids, and a Factor VIII cofactor, it hydrolyses one arginine-isoleucine bond in factor X to form factor Xa.

Factor IX is inhibited by antithrombin.^[2]

Factor IX expression increases with age in humans and mice. In mouse models mutations within the promoter region of factor IX have an age-dependent phenotype.^[4]

Domain architecture[link]

Factors VII, IX, and X all play key roles in blood coagulation and also share a common domain architecture.^[5] The factor IX protein is composed of four protein domains. These are the Gla domain, two tandem copies of the EGF domain and a C-terminal trypsin-like peptidase domain which carries out the catalytic cleavage.

The N-terminal EGF domain has been shown to at least in part be responsible for binding Tissue factor.^[5] Wilkinson et al. conclude that residues 88 to 109 of the second EGF domain mediate binding to platelets and assembly of the Factor X activating complex.^[6]

The structures of all four domains have been solved. A structure of the two EGF domains and trypsin like domain was determined for the pig protein.^[7] The structure of the Gla domain, which is responsible for Ca(II)-dependent phospholipid binding, was also determined by NMR.^[8]

Several structures of 'super active' mutants have been solved ^[9] which reveal the nature of Factor IX activation by other proteins in the clotting cascade.

Genetics[link]

The gene for factor IX is located on the X chromosome (Xq27.1-q27.2) and is therefore X-linked recessive: mutations in this gene affect males much more frequently than females. It was first cloned in 1982 by Kotoku Kurachi and Earl Davie.^[10]

Polly, a transgenic cloned Poll Dorset sheep carrying the gene for factor IX, was produced by Dr Ian Wilmut at the Roslin Institute in 1997.^[11]

Role in disease[link]

Deficiency of factor IX causes Christmas disease (hemophilia B).^[1] Over 100 mutations of factor IX have been described; some cause no symptoms, but many lead to a significant bleeding disorder. The original Christmas disease mutation was identified by sequencing of Christmas' DNA, revealing a mutation which changed a cysteine to a serine ^[12]. Recombinant factor IX is used to treat Christmas disease, and is commercially available as BeneFIX.^[13] Some rare mutations of factor IX result in elevated clotting activity, and can result in clotting diseases, such as deep vein thrombosis.^[14]

Factor IX deficiency is treated by injection of purified factor IX produced through cloning in various animal or animal cell vectors. Tranexamic acid may be of value in patients undergoing surgery who have inherited factor IX deficiency in order to reduce the perioperative risk of bleeding.^[15]

References[link]

Further reading[link]

External links[link]

• GeneReviews/NCBI/NIH/UW entry on Hemophilia B
• The MEROPS online database for peptidases and their inhibitors: S01.214
• An X(-mas) Factor that gets our vote- QUite Interesting PDB Structure article at PDBe

v t e PDB gallery 1cfh: STRUCTURE OF THE METAL-FREE GAMMA-CARBOXYGLUTAMIC ACID-RICH MEMBRANE BINDING REGION OF FACTOR IX BY TWO-DIMENSIONAL NMR SPECTROSCOPY   1cfi: NMR STRUCTURE OF CALCIUM ION-BOUND GAMMA-CARBOXY-GLUTAMIC ACID-RICH DOMAIN OF FACTOR IX   1edm: EPIDERMAL GROWTH FACTOR-LIKE DOMAIN FROM HUMAN FACTOR IX   1ixa: THE THREE-DIMENSIONAL STRUCTURE OF THE FIRST EGF-LIKE MODULE OF HUMAN FACTOR IX: COMPARISON WITH EGF AND TGF-A   1j34: Crystal Structure of Mg(II)-and Ca(II)-bound Gla Domain of Factor IX Complexed with Binding Protein   1j35: Crystal Structure of Ca(II)-bound Gla Domain of Factor IX Complexed with Binding Protein   1mgx: COAGULATION FACTOR, MG(II), NMR, 7 STRUCTURES (BACKBONE ATOMS ONLY)   1nl0: Crystal structure of human factor IX Gla domain in complex of an inhibitory antibody, 10C12   1rfn: HUMAN COAGULATION FACTOR IXA IN COMPLEX WITH P-AMINO BENZAMIDINE

Look up factor in Wiktionary, the free dictionary.

A factor, a Latin word meaning 'who/which acts', may refer to:

In commerce:

• Factor (agent), a person who acts for another, notably a mercantile and/or colonial agent
• Factor (Scotland), a person or firm managing a Scottish estate
• Factors of production, a resource used in the production of goods and services
• Factoring (finance), an entity providing commercial finance services
• Max Factor, a cosmetics company founded by Max Factor, Sr.

In science:

• An enzyme, proteins that catalyze chemical reactions
• Coagulation factors, substances essential for blood coagulation
• A phenomenon presumed to affect an experiment; see design of experiments
• Sun protection factor, a unit describing reduction in transmitted ultraviolet light
• Factor B and factor D, peptides involved in the alternate pathway of immune system complement activation.

In mathematics:

• Divisor, an integer which evenly divides a number without leaving a remainder
• Factorization, the decomposition of an object into a product of other objects
• Integer factorization, the process of breaking down a composite number into smaller non-trivial divisors
• A coefficient, a multiplicative factor in an expression, usually a number
• A von Neumann algebra with a trivial center
• Factor (graph theory), a spanning subgraph
• Any finite contiguous subsequence of a word

In statistics

• Factor analysis is the study of how factors or certain variables affect other variables.

In technology:

• Human factors, a profession that focuses on how people interact with products, tools, or procedures

In computer science and information technology:

• Authentication factor, a piece of information used to verify a person's identity for security purposes
• Factor (programming language), a concatenative stack-oriented programming language
• A substring, a subsequence of consecutive symbols in a string

In television:

• The O'Reilly Factor, an American talk show hosted by Bill O'Reilly on Fox News
• The Krypton Factor, a British game show hosted by Gordon Burns, formerly on ITV
  • The Krypton Factor (US game show) American version

People:

• Max Factor, Sr., a Polish-American businessman and cosmetician
• Max Factor, Jr., son of the above, born Francis Factor
• John Factor, a Prohibition-era gangster

Organizations:

• FACTOR, the Foundation to Assist Canadian Talent on Records

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.

Justin Bieber
Justin Bieber at the NRJ Music Awards in Cannes, France in 2012
Background information
Birth name	Justin Drew Bieber[1]
Born	(1994-03-01) March 1, 1994 (age 18)[2] London, Ontario, Canada
Origin	Stratford, Ontario, Canada
Genres	Pop, R&B, teen pop[3][4][5]
Occupations	Singer-songwriter, musician, actor
Instruments	Vocals, guitar, piano, percussion,[6] trumpet[7]
Years active	2008–present
Labels	Island, RBMG
Associated acts	Usher, Ludacris
Website	justinbiebermusic.com

Justin Drew Bieber ( /ˈbiːbər/ BEE-bər, born March 1, 1994)^[2] is a Canadian Pop/R&B singer-songwriter, musician, and actor.^[3][5] Bieber was discovered in 2008 by Scooter Braun,^[8] who came across Bieber's videos on YouTube and later became his manager. Braun arranged for him to meet with Usher in Atlanta, Georgia, and Bieber was soon signed to Raymond Braun Media Group (RBMG), a joint venture between Braun and Usher,^[9] and then to a recording contract with Island Records offered by L.A. Reid.^[6][10] Bieber's debut single, "One Time", was released in 2009 and peaked in the top twenty in Canada and charted in the top thirty in several international markets. His debut album, the seven-track EP My World, followed in November 2009, and was soon certified platinum in the United States. He became the first artist to have seven songs from a debut album chart on the Billboard Hot 100.^[11]

Bieber's first full-length studio album, My World 2.0, was released in March 2010. It debuted at number one or within the top ten in several countries and was certified platinum in the United States. It was preceded by the worldwide top-ten single, "Baby". The music video of "Baby" is currently ranked as the most viewed and most discussed YouTube video.^[12] Bieber followed up the release of his debut album with his first headlining tour, the My World Tour, the remix albums My Worlds Acoustic and Never Say Never – The Remixes, and the 3D biopic-concert film Justin Bieber: Never Say Never, that nearly matched the record for the biggest opening weekend gross for a concert-film. Bieber released his second studio album, Under the Mistletoe, in November 2011, which debuted at number one on the Billboard 200. Bieber has received numerous awards, including Artist of the Year at the 2010 American Music Awards, and has been nominated for such awards as Best New Artist and Best Pop Vocal Album at the 53rd Grammy Awards. In 2012, Bieber was named Forbes 3rd most powerful celebrity in the world, earning $55 million. As of May 2012, Bieber has sold 15 million albums.^[13]

Early life[link]

Bieber was born on March 1, 1994, in London, Ontario in St Joseph's Hospital,^[14][15] and was raised in Stratford, Ontario.^[16] Bieber's mother, Patricia Lynn "Pattie" Mallette, was 18 years old when she became pregnant. Mallette, originally from Stratford, raised her son with the help of her parents, Bruce and Diane.^[17] Mallette worked a series of low-paying office jobs, raising Bieber as a single mother in low-income housing. Bieber has maintained contact with his father, Jeremy Jack Bieber, who married another woman and had two children.^[18][19][20] Bieber's great-grandfather was from Germany.^[21] Bieber's mother's ancestry is French Canadian.^[22] Bieber attended a French immersion elementary school in Stratford called Jeanne Sauvé Catholic School.^[17]

During his childhood, Bieber was interested in hockey, soccer, and chess; he often kept his musical aspirations to himself.^[18] As he grew up, Bieber taught himself to play the piano, drums, guitar, and trumpet.^[16][23] In early 2007, when he was twelve, Bieber sang Ne-Yo's "So Sick" for a local singing competition in Stratford and was placed second.^[6][23] Mallette posted a video of the performance on YouTube for their family and friends to see. She continued to upload videos of Bieber singing covers of various R&B songs, and Bieber's popularity on the site grew.^[10] Chris Hicks, Bieber's A&R at Island/Def Jam, explained the young artist's huge online following to HitQuarters by saying:

"He was doing something different. He was an attractive white kid singing very soulful R&B hits. That set him apart immediately from anyone in his range because no one was covering or singing these kind of records. But equally important was that you believed in these songs – it was real. And you wanted to hear more."^[24]

Career[link]

[edit] 2008–09: Discovery and My World

While searching for videos of a different singer, Scooter Braun, a former marketing executive of So So Def, clicked on one of Bieber's 2007 videos by accident.^[18] Impressed, Braun tracked down the theater Bieber was performing in, located Bieber's school, and finally contacted Mallette. Mallette was reluctant because of Braun's Jewish religion; she remembered praying, "God, I gave him to you. You could send me a Christian man, a Christian label! ... you don’t want this Jewish kid to be Justin’s man, do you?"^[18] However, after praying with her church elders and receiving their encouragement, she permitted Braun to fly Bieber, then 13,^[10] to Atlanta, Georgia, to record demo tapes.^[18] A week after arriving, Bieber sang for R&B singer/songwriter Usher.^[25] Bieber was soon signed to Raymond Braun Media Group (RBMG), a joint venture between Braun and Usher.^[9] Justin Timberlake was also reportedly in the running to sign Bieber, but lost the bidding war to Usher.^[9][26] Usher then sought assistance in finding a label home for the artist from then manager Chris Hicks, who helped engineer an audition with his contact Antonio L.A. Reid of Island Def Jam Music Group.^[24] Reid signed Bieber to Island Records in October 2008 (resulting in a joint venture between RBMG and Island Records) and appointed Hicks as executive Vice-President of Def Jam where he would be able manage Bieber's career at the label.^{[6][9][10][24]} At that point, Bieber and his mother moved to Atlanta temporarily, also the home of Usher and Braun, to record and get counseling from Braun.^[9] Braun became Bieber's manager.^[10]

Bieber in September 2009 at the Nintendo World Store

Bieber's first single, "One Time", was released to radio while Bieber was still recording his debut album.^[27] The song reached number 12 on the Canadian Hot 100 during its first week of release in July 2009,^[10] and later peaked at number 17 on the Billboard Hot 100. During fall 2009 it had success in international markets.^[28] The song was certified Platinum in Canada and the US and Gold in Australia and New Zealand.^[29][30][31] Bieber's first release, an extended play entitled My World, was released on November 17, 2009. The album's second single, "One Less Lonely Girl", and two promo singles, "Love Me", and "Favorite Girl", were released exclusively on the iTunes store and charted within the top forty of the Billboard Hot 100.^[28] "One Less Lonely Girl" was later also released to radio and peaked within the top fifteen in Canada and the US, being certified Gold in the latter.^[28] My World was eventually certified Platinum in the US and Double Platinum in both Canada and the UK.^[31][32][33] To promote the album, Bieber performed on several live shows such as mtvU's VMA 09 Tour, European program The Dome, YTV's The Next Star, The Today Show,^[34][35] The Wendy Williams Show, Lopez Tonight, The Ellen DeGeneres Show, It's On with Alexa Chung, Good Morning America, Chelsea Lately, and BET's 106 & Park with Rihanna. Bieber also guest starred in an episode of True Jackson, VP in late 2009.^[36]

Bieber performed Stevie Wonder's "Someday at Christmas" for U.S. President Barack Obama and first lady Michelle Obama at the White House for Christmas in Washington, which was broadcast on December 20, 2009, on U.S. television broadcaster TNT.^[37] Bieber was also one of the performers at Dick Clark's New Year's Rockin' Eve with Ryan Seacrest on December 31, 2009.^[38] Bieber was a presenter at the 52nd Grammy Awards on January 31, 2010. He was invited to be a vocalist for the remake of We Are The World (a song written by Michael Jackson and Lionel Richie) for its 25th anniversary to benefit Haiti after the earthquake. Bieber sings the opening line, which was sung by Lionel Richie in the original version.^[39] On March 12, 2010, a version of K'naan's "Wavin' Flag" recorded by a collective of Canadian musicians known as Young Artists for Haiti was released. Bieber is featured in the song, performing the closing lines.

[edit] 2010–11: My World 2.0 and Never Say Never film

"Baby", the lead single from his debut album, My World 2.0, which features Ludacris, was released in January 2010 and became his biggest hit thus far, charting at number five in the U.S. and reaching the top ten in seven other countries.^[28] Two promo singles "Never Let You Go", and "U Smile" were top thirty hits on the U.S. Hot 100, and top twenty hits in Canada.^[28] According to review aggregator Metacritic, the album has received "generally favorable reviews".^[40] It debuted at number one on the U.S. Billboard 200, making Bieber the youngest solo male act to top the chart since Stevie Wonder in 1963.^[41] My World 2.0 also debuted at number one on the Canadian Albums Chart, Irish Albums Chart, Australian Albums Chart, and the New Zealand Albums Chart^[28] and reached the top ten of fifteen other countries.^[42][43] To promote the album, Bieber appeared on several live programs including The View, the 2010 Kids Choice Awards, Nightline, The Late Show with David Letterman, The Dome and 106 and Park.^[44] Bieber collaborated with Sean Kingston on his single "Eenie Meenie" which also appeared on Bieber's debut album. The song reached the top ten in the United Kingdom and Australia, and the top-twenty of most other markets.

Bieber performing at the Conseco Fieldhouse, in August 2010

On April 10, 2010, Bieber was the musical guest on Saturday Night Live.^[45] On July 4, 2010, Bieber performed at the Macy's Fourth of July Fireworks Spectacular in New York City.^[46] The second single from My World 2.0, "Somebody to Love", was released in April 2010, and a remix was released featuring Bieber's mentor Usher. The single reached number ten in Canada, number fifteen in the United States, and the top twenty in multiple international countries.

On June 23, 2010, Bieber went on his first official headlining tour, the My World Tour, starting in Hartford, Connecticut, to promote My World and My World 2.0.^[47] In July 2010, it was reported that Bieber was the most searched for celebrity on the Internet.^[48] That same month his music video, "Baby", surpassed Lady Gaga's "Bad Romance" to become the most viewed, and most disliked YouTube video ever.^[49] In September 2010, it was reported that Bieber accounted for three percent of all traffic on Twitter, according to an employee of the social-networking site.^[50]

Bieber began recording his second album in July 2010 in New York City.^[51] At this point, because of puberty, his voice was deeper than it was when he recorded his first album. In April 2010, the singer discussing his vocals remarked, "It cracks. Like every teenage boy, I'm dealing with it and I have the best vocal coach in the world. [...] Some of the notes I hit on "Baby" I can't hit anymore. We have to lower the key when I sing live."^[52]

Bieber performing in Jakarta during his My World Tour.

Bieber guest-starred in the season premiere of the CBS crime drama CSI: Crime Scene Investigation, which aired on September 23, 2010. He played a "troubled teen who is faced with a difficult decision regarding his only brother", who is also a serial bomber. Bieber was also in a subsequent episode which aired on February 17, 2011, in which his character is killed.^[53] Bieber performed a medley of "U Smile", "Baby", and "Somebody to Love" and briefly played the drums at the 2010 MTV Video Music Awards on September 12, 2010.^[54] Bieber announced in October 2010 that he would release an acoustic album, called My Worlds Acoustic.^[55] It was released on Black Friday in the United States and featured acoustic versions of songs from his previous albums, and accompanied the release of a completely new song titled "Pray".^[56]

A 3-D part-biopic, part-concert film starring Bieber entitled Justin Bieber: Never Say Never, was released on February 11, 2011, directed by Step Up 3D director Jon Chu. It topped the box office with an estimated gross of $12.4 million on its opening day from 3,105 theaters.^[57] It grossed $30.3 million for the weekend and was narrowly beaten by the romantic comedy Just Go With It, which grossed $31 million.^[58] Never Say Never is said to have exceeded industry expectations, nearly matching the $31.1 million grossed by Miley Cyrus's 2008 3-D concert film, Hannah Montana & Miley Cyrus: Best of Both Worlds Concert, which holds the record for the top debut for a music-documentary.^[59][60] Never Say Never grossed a total of $98,441,954 worldwide.^[61] The film is accompanied by his second remix album, Never Say Never – The Remixes, released February 14, 2011, and features remixes of songs from his debut album, with guest appearances from Miley Cyrus, Chris Brown, and Kanye West, among others.^[62]

[edit] 2011–present: Under The Mistletoe and Believe

On February 27, 2011, Bieber attended the 2011 Vanity Fair Oscar Party with American actress and singer Selena Gomez,^[63] confirming several months of media speculation about a romantic relationship between the pair.^{[64][65][66][67][68][69]}

In June 2011, Bieber was ranked number 2 on the Forbes list of Best-Paid Celebrities under 30. He is the youngest star and 1 of 7 musicians on the list raking in with $53 million earned in a 12 month period.^[70] On November 1, 2011, Bieber released Under the Mistletoe, his second studio album.^[71] It debuted at number one on the Billboard 200, selling 210,000 copies in its first week of release.^[72]

In late 2011, Bieber began recording his third studio album, entitled Believe. Kanye West and Drake are confirmed to be featured on the album.^[73] On February 22, 2012, Bieber announced via Twitter that the first single off Believe will be released in March 2012.^[74] The following week, Bieber appeared on The Ellen DeGeneres Show to announce that the first single will be called "Boyfriend" and was released on March 26, 2012.^[75] The song was co-written by Mike Posner.^[76] The second single, Die In Your Arms, was released on May 29th, 2012. ^[77]

Image[link]

Justin Bieber has a higher score on the Klout online "influence" scale than Barack Obama or The Dalai Lama.^[78] According to Jan Hoffman of The New York Times, part of Bieber's appeal stems from his YouTube channel. Long before he released his EP, My World, in mid-November, the YouTube videos attracted millions of views.^[18] Braun recognized the appeal. Prior to flying him to Atlanta, Braun wanted to "build him up more on YouTube first" and had Bieber record more home videos for the channel. "I said: 'Justin, sing like there’s no one in the room. But let's not use expensive cameras.' We'll give it to kids, let them do the work, so that they feel like it's theirs", recalled Braun.^[18] Bieber continues to upload videos to the same channel and has opened a Twitter account, from which he interacts with fans regularly;^[10] his account was reported in November 2010 to have over 6 million followers.^[79] Since then he has been consistently gaining followers at an average of 24,000 per day.^[80] The accounts also serve marketing purposes; for example, Bieber's music video for "One Time" only began selling quickly after it was uploaded to YouTube.^[81]

Bieber performing "Favorite Girl" in Zurich, Switzerland April 2011.

Usher comments that while he and Bieber were both signed at the same age, "I had the chance to ramp up my success, where this has happened to Bieber abruptly." As a result, Usher, Braun, Bieber's bodyguard Kenny, and other adults surrounding Bieber constantly coach him on handling fame and his public image.^[18] After signing Bieber, Usher appointed one of his former assistants, Ryan Good, to be Bieber's road manager and stylist. Good, once nicknamed Bieber's "swagger coach", created a "streetwise look" for the singer which consisted of baseball caps, hoodies, dog chains and flashy sneakers. Amy Kaufman of The Los Angeles Times comments, "Though a product of a middle-class suburban upbringing in Stratford, Ontario, Bieber's manner of dress and speech ("Wassup man, how you doin'?" or "It's like, you know, whateva' ") suggest he's mimicking his favorite rappers."^[82]

Bieber is often featured in teen magazines such as Tiger Beat,^[18] and has been labeled as a "teen heartthrob".^[83] Bieber has released a collection of nail varnishes to raise awareness for charity.^[84] Wax statues of Bieber are on display at Madame Tussauds wax museums in New York, Amsterdam and London.^[85] His change of hairstyle in 2010, and the consequent alterations to Bieber products, led to it being called 'the most expensive musical haircut of all time;^[86] one company spent $100,000 to fix its dolls for the 2011 Christmas season.^[87]

Bieber has been criticized for looking and sounding younger than his age, his teen-pop music, image, and frequent media attention.^[88] He has been a frequent target of Internet bloggers and message board posters, notably by users of Internet message board 4chan and users of YouTube.^[89] Nick Collins of The Daily Telegraph speculated that "Bieber's character also appears to strike a particularly sour note with his Internet critics, with many remarks commenting on his youthful appearance, his teen-pop songs, his image as a heart-throb to young teenage girls and his manner of speech".^[90]

Personal views and life[link]

Bieber is a Christian,^[91] and said he has a relationship with Jesus, talks to him and that "he's the reason I'm here".^[92]

Bieber's comments in a February 2011 profile in Rolling Stone sparked controversy.^[93] Asked about abstinence, Bieber responded, "I don't think you should have sex with anyone unless you love them." He said he does not "believe in abortion" and that it is "like killing a baby".^[94] He described sexual orientation as "everyone's own decision."^[95] Bieber has contributed to the It Gets Better Project,^[96] which aims to prevent suicide among LGBT youth.^[97]

Bieber has said he is not interested in obtaining United States citizenship and has criticized America's health care system. Praising Canada as being "the best country in the world", he cited its health care system as a model example.^[94]

In May 2012, Bieber purchased a 10,000 square-foot mansion on 1.3 acres of land, located in the community of Calabasas, California, a suburb of Los Angeles.^[98]

Twitter[link]

As of April 2012^[update], Bieber's Twitter account (@justinbieber) is the second most popular celebrity account behind that of Lady Gaga.^[99] By mid-April 2012, he had over 20 million followers.^[100][101] His follower acquisition is one new follower every other second.^[102][103] His popularity on Twitter at one point accounted for three percent of all Twitter related traffic, with a Twitter employee commenting that "racks of servers are dedicated" to Bieber.^{[103][104][105][106][107][108][109][110][111][112]} This resulted in over 180 million page views for the service each month.^[105] Bieber was frequently a trending topic on Twitter when the feature first launched^[105] because his fans frequently discussed him on the network. ^[113] and was named the top trending star on Twitter in 2010;^[114] Klout gave his account a score of 100.^[115][116]

The size of Bieber's and Gaga's follower bases are cited as a reason why marketers should pay attention to Twitter:^[117] with an ability to reach millions of people with a single tweet.^[117] 8.3% of tweets mentioning "bieber" were semi-automated and probably Twitter related spam.^[118] Research done about Twitter and the 2011 Egyptian revolution includes Bieber as he made tweets about the topic at a time when he had roughly 8 million followers. His multiple tweets resulted in 32,000 responses each, which made Bieber's Twitter account one of the single largest nodes for discussion about the uprising one of the largest on Twitter.^[119][120]

In March 2012, Bieber fans launched an unsuccessful attempt to unseat Lady Gaga as the most popular celebrity on Twitter. Neither Bieber nor Lady Gaga discussed their mutual fanbase's campaigns on Twitter.^[121]

Discography[link]

Justin Bieber portal

• My World 2.0 (2010)
• Under the Mistletoe (2011)
• Believe (2012)

Tours[link]

• 2009: Urban Behavior Tour
• 2010–2011: My World Tour
• 2012-2013: Believe Tour

Filmography[link]

Awards and nominations[link]

References[link]