PIK3R1 : phosphoinositide-3-kinase regulatory subunit 1

Description

The PIK3R1 (phosphoinositide-3-kinase regulatory subunit 1) is a protein-coding gene located on chromosome 5.

The PIK3R1 gene provides instructions for making a part (subunit) of an enzyme called phosphatidylinositol 3-kinase (PI3K). The primary function of the subunit is to regulate the enzyme's activity. Several slightly different versions of this regulatory subunit are produced from the PIK3R1 gene; the most abundant of these is called p85 alpha (p85α).PI3K is a kinase, which means that it adds a cluster of oxygen and phosphorus atoms (a phosphate group) to other proteins through a process called phosphorylation. PI3K phosphorylates certain signaling molecules, which triggers a series of additional reactions that transmit chemical signals within cells. PI3K signaling is important for many cell activities, including cell growth and division (proliferation), movement (migration) of cells, production of new proteins, transport of materials within cells, and cell survival. Studies suggest that PI3K signaling may be involved in how cells regulate several hormones. One of these hormones is insulin, which helps control levels of blood glucose, also called blood sugar. PI3K signaling may also play a role in the maturation of fat cells (adipocytes).

PIK3R1 binds to activated protein-tyrosine kinases through its SH2 domain, acting as an adapter that mediates the association of the p110 catalytic unit to the plasma membrane. It is essential for insulin-stimulated glucose uptake and glycogen synthesis in insulin-sensitive tissues. PIK3R1 plays a significant role in signaling pathways triggered by FGFR1, FGFR2, FGFR3, FGFR4, KITLG/SCF, KIT, PDGFRA, and PDGFRB. It also participates in ITGB2 signaling. PIK3R1 modulates the cellular response to ER stress by promoting the nuclear translocation of XBP1 isoform 2, in an ER stress- and/or insulin-dependent manner during metabolic overloading in the liver, thus contributing to improved glucose tolerance.

PIK3R1 is also known as AGM7, GRB1, IMD36, p85, p85-ALPHA, p85alpha.

Associated Diseases

• Agammaglobulinemia 7, autosomal recessive
• SHORT syndrome
• Short syndrome
• Immunodeficiency 36
• Activated PI3K-delta syndrome
• Autosomal agammaglobulinemia
• Short stature, hyperextensibility, hernia, ocular depression, Rieger anomaly, and teething delay