Phosphoinositide-3-Kinase Regulatory Subunit 4 (PIK3R4)

In yeast, the vps15 gene product is a 150-kD serine/threonine kinase that forms a complex with a phosphatidylinositol 3-kinase, vps34 (PIK3C3); in human this complex is involved in protein trafficking. By screening a cDNA library, Panaretou et al. (1997) cloned the homolog of the yeast vps15 gene, which they termed p150. The p150 cDNA encodes a predicted polypeptide of 1,358 amino acids.

The amino acid sequence is 29.6% identical to that of yeast vps15 protein. Northern blot analysis revealed that the p150 gene is ubiquitously expressed as a 5.5-kb transcript. Panaretou et al. (1997) found that the p150 gene interacts with PIK3C3 in vivo.