Class I PI 3-kinases are a subgroup of the enzyme family, phosphoinositide 3-kinase that possess a common protein domain structure, substrate specificity, and method of activation. Class I PI 3-kinases are further divided into two subclasses, class IA PI 3-kinases and class IB PI 3-kinases.
Class III PI 3-kinase is a subgroup of the enzyme family, phosphoinositide 3-kinase that share a common protein domain structure, substrate specificity and method of activation.
The phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha, also called p110α protein, is a class I PI 3-kinase catalytic subunit. The human p110α protein is encoded by the PIK3CA gene.
Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta isoform also known as phosphoinositide 3-kinase (PI3K) delta isoform or p110δ is an enzyme that in humans is encoded by the PIK3CD gene.
Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit gamma isoform is an enzyme that in humans is encoded by the PIK3CG gene.
In enzymology, a phosphatidylinositol-4,5-bisphosphate 3-kinase is an enzyme that catalyzes the chemical reaction
Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit beta isoform is an enzyme that in humans is encoded by the PIK3CB gene.
Arf-GAP with GTPase, ANK repeat and PH domain-containing protein 2 is a protein that in humans is encoded by the AGAP2 gene.
Phosphatidylinositol 3-kinase regulatory subunit gamma is an enzyme, which in humans is encoded by the PIK3R3 gene.
Phosphoinositide 3-kinase adapter protein 1 is an enzyme that in humans is encoded by the PIK3AP1 gene.
Phosphoinositide 3-kinase regulatory subunit 5 is an enzyme that in humans is encoded by the PIK3R5 gene.
PKN3 is a protein kinase C-related molecule and thought to be an effector mediating malignant cell growth downstream of activated phosphoinositide 3-kinase (PI3K). It is thought that chronic activation of the phosphoinositide 3-kinase (PI3K)/PTEN signal transduction pathway contributes to metastatic cell growth and that PKN3 may mediate that growth.1
The Akt Pathway, or PI3K-Akt Pathway is a signal transduction pathway that promotes survival and growth in response to extracellular signals. Key proteins involved are PI3K and Akt.
The PI3K/AKT/mTOR pathway is an intracellular signaling pathway important in regulating the cell cycle. Therefore, it is directly related to cellular quiescence, proliferation, cancer, and longevity. PI3K activation phosphorylates and activates AKT, localizing it in the plasma membrane. AKT can have a number of downstream effects such as activating CREB, inhibiting p27, localizing FOXO in the cytoplasm, activating PtdIns-3ps, and activating mTOR which can affect transcription of p70 or 4EBP1. There are many known factors that enhance the PI3K/AKT pathway including EGF, shh, IGF-1, insulin, and CaM. The pathway is antagonized by various factors including PTEN, GSK3B, and HB9. In many cancers, this pathway is overactive, thus reducing apoptosis and allowing proliferation. This pathway is necessary, however, to promote growth and proliferation over differentiation of adult stem cells, neural stem cells specifically. It is the difficulty in finding an appropriate amount of proliferation versus differentiation that researchers are trying to determine in order to utilize this balance in the development of various therapies. Additionally, this pathway has been found to be a necessary component in neural long term potentiation.
PASLI disease is a rare genetic disorder of the immune system. PASLI stands for “p110 delta activating mutation causing senescent T cells, lymphadenopathy, and immunodeficiency.” The immunodeficiency manifests as recurrent infections usually starting in childhood. These include bacterial infections of the respiratory system and chronic viremia due to Epstein-Barr virus (EBV) and/or cytomegalovirus (CMV). Individuals with PASLI disease also have an increased risk of EBV-associated lymphoma. Investigators Carrie Lucas, Michael Lenardo, and Gulbu Uzel at the National Institute of Allergy and Infectious Diseases at the U.S. National Institutes of Health and Sergey Nejentsev at the University of Cambridge, UK simultaneously described a mutation causing this condition which they called Activated PI3K Delta Syndrome (APDS).
Buparlisib is an investigational small molecule orally-available pan-class I phosphoinositide 3-kinase inhibitor.
