Phosphoinositide-3-Kinase Class 3 (PIK3C3)

Phosphoinositide (PI) 3-kinases are involved in both receptor-mediated signal transduction and intracellular trafficking. In yeast, the vps34 gene product is a PI 3-kinase that mediates the active diversion of proteins from the secretory pathway to vacuoles. Mammals appear to have a family of PI 3-kinases, which also includes PIK3CG and PIK3CA. The full-length PIK3C3 cDNA encodes an 887-amino acid polypeptide that is 37% identical to yeast vps34 over its entire length. Its predicted and observed molecular mass is approximately 100 kD. PIK3C3 gene was expressed as a 3.7-kb transcript in all human tissues examined.The PIK3C3 gene does not associate with the p85 regulatory subunit but does form a complex with p150, a mammalian homolog of another protein in the yeast vps pathway.