Phosphoinositide 3-Kinase Review of Classes and Role in Mammals

Enzymes play an important role in biological systems as signaling molecules. Signals contribute to catalytic chemical reactions by enzymes which allow them to pass through the path with lower activation energy (Domin and Waterfield, 1997). Enzymes are made from amino acid chains, or amino acid chains joined by peptide bonds also known as proteins. One enzyme pathway of particular interest is phosphoinositide 3-kinase (PI3K). This enzyme is a lipid kinase with further signaling activity, also known as cascade induction once activated.

The Vps34 regulatory complex consists of lipid kinase Vps 34 (also known as class III phosphatidylinositol 3 (PI 3) kinase), Atg 6 (called Beclin 1 in mammals) and protein kinase Vps 15 (p 150 in mammals) (Simonsen and Tooze 2009). This core complex regulates the formation of PI 3 phosphate (PI 3 P) lipids and is required for a variety of intracellular vesicular trafficking pathways including endocytosis and autophagy. The Vps34 complex has different proteins associated with it thought to be specific for a regulated vesicular process and in the context of autophagy they include Atg 14 and Vps 38 (UVRAG in mammals). Vps34 complex components are localized in PAS and are necessary for autophagosome formation (Juhász et al., 2008). Several studies have shown that mTOR and Vps 34 are in a common regulatory pathway (Byfield et al., 2005; Nobukuni et al., 2008; Jaber et al., 2012).

Recent studies have shown that phosphoinositide 3-kinase (PI3K) / Akt signaling regulates fibrotic responses including collagen synthesis and cell proliferation. Jung et al. Synthesized a novel PI3K inhibitor HS-173, found that it inhibited proliferation of fibroblasts and induced apoptosis in a dose-dependent manner. These findings are in stark contrast to our results, but this difference is due to the fact that they were obtained in vivo, or the fact that our samples contain stable plaques, probably activated and achieved through apoptosis . It is well known that when cells lack growth factors, for example because of excessive tissue growth they stop growing and often die by apoptosis.