ITPKB

{{cs1 config|name-list-style=vanc}} {{Short description|Protein-coding gene in the species Homo sapiens}} {{Infobox_gene}} '''Inositol-trisphosphate 3-kinase B''' is an enzyme that in humans is encoded by the ''ITPKB'' gene.<ref name="pmid1654894">{{cite journal |vauthors=Takazawa K, Perret J, Dumont JE, Erneux C | title = Molecular cloning and expression of a new putative inositol 1,4,5-trisphosphate 3-kinase isoenzyme | journal = Biochem J | volume = 278 | issue = 3| pages = 883–6 |date=Oct 1991 | pmid = 1654894 | pmc = 1151429 | doi = 10.1042/bj2780883}}</ref><ref name="pmid1330886">{{cite journal |vauthors=Erneux C, Roeckel N, Takazawa K, Mailleux P, Vassart G, Mattei MG | title = Localization of the genes for human inositol 1,4,5-trisphosphate 3-kinase A (ITPKA) and B (ITPKB) to chromosome regions 15q14-q21 and 1q41-q43, respectively, by in situ hybridization | journal = Genomics | volume = 14 | issue = 2 | pages = 546–7 |date=Dec 1992 | pmid = 1330886 | doi =10.1016/S0888-7543(05)80265-4 }}</ref>

== Function ==

The protein encoded by the ITPKB gene is one of 3 isoforms of Inositol-trisphosphate 3-kinase expressed in humans. ITPKB protein regulates inositol phosphate metabolism by phosphorylation of second messenger inositol 1,4,5-trisphosphate, which releases calcium from intracellular store in the endoplasmic reticulum by gating the inositol trisphosphate receptor. ITPKB produces Ins(1,3,4,5)P<small>4</small>, which does ''not'' gate the inositol trisphosphate receptor. The enzyme specifically phosphorylates the 1,4,5 isomer of IP<small>3</small>. The activity of this encoded protein is responsible for regulating the levels of a large number of inositol polyphosphates that are important in cellular signaling. Both calcium/calmodulin and protein phosphorylation mechanisms control its activity.<ref>{{cite web | title = Entrez Gene: ITPKB inositol 1,4,5-trisphosphate 3-kinase B| url = https://www.ncbi.nlm.nih.gov/gene?Db=gene&Cmd=ShowDetailView&TermToSearch=3707}}</ref> Itpkb regulates immune cell function and is required for T and B cell development.<ref>{{cite journal | pmid = 20336153 | doi=10.1038/nri2745 | volume=10 | issue=4 | title=Regulation of immune cell development through soluble inositol-1,3,4,5-tetrakisphosphate | pmc=2922113 |date=April 2010 | journal=Nat. Rev. Immunol. | pages=257–71 |vauthors=Sauer K, Cooke MP }}</ref>

==References== {{reflist}}

==Further reading== {{refbegin | 2}} *{{cite journal |vauthors=Szlufcik K, Missiaen L, Parys JB, etal |title=Uncoupled IP3 receptor can function as a Ca2+-leak channel: cell biological and pathological consequences. |journal=Biol. Cell |volume=98 |issue= 1 |pages= 1–14 |year= 2006 |pmid= 16354157 |doi= 10.1042/BC20050031 |s2cid=36990427 |doi-access= }} {{refend}}