Phosphatidylinositol 3-kinase regulatory subunit alpha is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

that in humans is encoded by the ''PIK3R1''

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

Function

Phosphatidylinositol 3-kinase Phosphoinositide 3-kinases (PI3Ks), also called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival and intracellular trafficking, which i ...

phosphorylates the

inositol Inositol, or more precisely ''myo''-inositol, is a carbocyclic sugar that is abundant in the brain and other mammalian tissues; it mediates cell signal transduction in response to a variety of hormones, neurotransmitters, and growth factors and ...

ring of

phosphatidylinositol Phosphatidylinositol (or Inositol Phospholipid) consists of a family of lipids as illustrated on the right, where red is x, blue is y, and black is z, in the context of independent variation, a class of the phosphatidylglycerides. In such molecul ...

at the 3-prime position. The enzyme comprises a 110 kD catalytic subunit and a regulatory subunit of either 85, 55, or 50 kD. This gene encodes the 85 kD regulatory subunit. Phosphatidylinositol 3-kinase plays an important role in the metabolic actions of

insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism o ...

, and a mutation in this gene has been associated with

insulin resistance Insulin resistance (IR) is a pathological condition in which cell (biology), cells fail to respond normally to the hormone insulin. Insulin is a hormone that facilitates the transport of glucose from blood into cells, thereby reducing blood gluco ...

. Alternative splicing of this gene results in three transcript variants encoding different isoforms.

Clinical significance

Mutations in ''PIK3R1'' are implicated in cases of

breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...

. Mutations in PIK3R1 are associated to

SHORT syndrome SHORT syndrome is a medical condition in which affected individuals have multiple birth defects in different organ systems. It was characterized in 1975. Presentation SHORT is an acronym for short stature, hyperextensibility of joints and/or in ...

Interactions

PIK3R1 has been shown to

interact Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizati ...

with: *

ADAM12 Disintegrin and metalloproteinase domain-containing protein 12 (previously Meltrin) is an enzyme that in humans is encoded by the ''ADAM12'' gene. ADAM12 has two splice variants: ADAM12-L, the long form, has a transmembrane region and ADAM12-S, a ...

, *

BCAR1 Breast cancer anti-estrogen resistance protein 1 is a protein that in humans is encoded by the ''BCAR1'' gene. Gene BCAR1 is localized on chromosome 16 on region q, on the negative strand and it consists of seven exons. Eight different gene is ...

, * CBLB, *

CD117 Proto-oncogene c-KIT is the gene encoding the receptor tyrosine kinase protein known as tyrosine-protein kinase KIT, CD117 (cluster of differentiation 117) or mast/stem cell growth factor receptor (SCFR). Multiple transcript variants encoding diff ...

, *

CD28 CD28 (Cluster of Differentiation 28) is one of the proteins expressed on T cells that provide co-stimulatory signals required for T cell activation and survival. T cell stimulation through CD28 in addition to the T-cell receptor ( TCR) can provid ...

, *

CD7 CD7 (Cluster of Differentiation 7) is a protein that in humans is encoded by the ''CD7'' gene. Function This gene encodes a transmembrane protein which is a member of the immunoglobulin superfamily. This protein is found on thymocytes and matur ...

, *

CENTG1 Arf-GAP with GTPase, ANK repeat and PH domain-containing protein 2 is a protein that in humans is encoded by the ''AGAP2'' gene. Interactions CENTG1 has been shown to interact with: * EPB41L1, * HOMER1 and * PIK3R1 Phosphatidylinositol 3-kin ...

, * CBL, *

EPHA2 EPH receptor A2 (ephrin type-A receptor 2) is a protein that in humans is encoded by the ''EPHA2'' gene. Function This gene belongs to the ephrin receptor subfamily of the protein- tyrosine kinase family. EPH and EPH-related receptors have be ...

, * EPOR, *

ERBB3 Receptor tyrosine-protein kinase erbB-3, also known as HER3 (human epidermal growth factor receptor 3), is a membrane bound protein that in humans is encoded by the ''ERBB3'' gene. ErbB3 is a member of the epidermal growth factor receptor (EGFR/ ...

, * EZR, *

FCGR2A Low affinity immunoglobulin gamma Fc region receptor II-a is a protein that in humans is encoded by the ''FCGR2A'' gene. Interactions FCGR2A has been shown to interact with PIK3R1 and Syk. See also * CD32 CD32 (cluster of differentiation 3 ...

, *

GAB1 GRB2-associated-binding protein 1 is a protein that in humans is encoded by the ''GAB1'' gene. Function The protein encoded by this gene is a member of the IRS1-like multisubstrate docking protein family. The encoded protein is an important me ...

, *

GAB2 GRB2-associated-binding protein 2 also known as GAB2 is a protein that in humans is encoded by the ''GAB2'' gene. GAB2 is a docking protein with a conserved, folded PH domain attached to the membrane and a large disordered region, which hosts int ...

, * Grb2, *

HRAS GTPase HRas, from "Harvey Rat sarcoma virus", also known as transforming protein p21 is an enzyme that in humans is encoded by the gene. The ''HRAS'' gene is located on the short (p) arm of chromosome 11 at position 15.5, from base pair 522,241 ...

, *

IRS1 Insulin receptor substrate 1 (IRS-1) is a signaling adapter protein that in humans is encoded by the ''IRS-1'' gene. It is a 131 kDa protein with amino acid sequence of 1242 residues. It contains a single pleckstrin homology (PH) domain at the N-te ...

* IRS2, * IL1R1, *

JAK2 Janus kinase 2 (commonly called JAK2) is a non-receptor tyrosine kinase. It is a member of the Janus kinase family and has been implicated in signaling by members of the type II cytokine receptor family (e.g. interferon receptors), the GM-CSF rece ...

, *

KHDRBS1 KH domain-containing, RNA-binding, signal transduction-associated protein 1 is a protein that in humans is encoded by the ''KHDRBS1'' gene. This gene encodes a member of the K homology domain-containing, RNA-binding, signal transduction-associate ...

, * LTK, *

LAT Lat or LAT may refer to: Places * Lat, Fuman, village in Gilan Province, Iran * Lat, Rasht, village in Gilan Province, Iran * Lat, Mazandaran, village in Iran * Lat-e Disar, village in Mazandaran Province, Iran * Lat, Qazvin, village in I ...

, * LCP2, * PIK3CD, *

PTK2 PTK2 protein tyrosine kinase 2 (PTK2), also known as focal adhesion kinase (FAK), is a protein that, in humans, is encoded by the ''PTK2'' gene. PTK2 is a focal adhesion-associated protein kinase involved in cellular adhesion (how cells stick to ...

, * SHB, *

TUBA1B Tubulin alpha-1B chain is a protein that in humans is encoded by the ''TUBA1B'' gene. Interactions TUBA1B has been shown to interact with PIK3R1 Phosphatidylinositol 3-kinase regulatory subunit alpha is an enzyme that in humans is encoded by the ...

, *

TYRO3 Tyrosine-protein kinase receptor TYRO3 is an enzyme that in humans is encoded by the ''TYRO3'' gene. Interactions TYRO3 has been shown to interact with: * GAS6, and * PIK3R1 Phosphatidylinositol 3-kinase regulatory subunit alpha is an enzyme ...

, *

VAV1 Proto-oncogene vav is a protein that in humans is encoded by the ''VAV1'' gene. Function The protein encoded by this proto-oncogene is a member of the Dbl family of guanine nucleotide exchange factors (GEF) for the Rho family of GTP binding ...

, and *

WAS Was or WAS may refer to: * ''Was'', a past-tense form of the English copular verb ''to be'' People * David Was (born c. 1952), the stage name of multi-instrumentalist and songwriter David Weiss * Don Was (born 1952), the stage name of bass guita ...

Function

Clinical significance

Interactions

References

Further reading