Protein kinase B gamma (PKB-gamma), also known as AKT3, is one of three closely related serine/threonine-protein kinases: AKT1/alpha, AKT2/beta and AKT3/gamma. PKBs contain an N-terminal pleckstrin homology (PH) domain and a C-terminal catalytic domain []. PKB-gamma is predominantly expressed in neuronal tissues. Mice deficient in PKB-gamma show a reduction in brain weight due to the decreases in cell size and cell number []. PKB-gamma has also been shown to be upregulated in estrogen-deficient breast cancer cells, androgen-independent prostate cancer cells, and primary ovarian tumours []. It acts as a key mediator in the genesis of ovarian cancer [].
Protein kinase B (PKB), also called Akt or RAC, is a phosphatidylinositol 3'-kinase (PI3K)-dependent Ser/Thr kinase which alters the activity of the targeted protein []. Akt regulates numerous cellular processes, including cell growth, differentiation, proliferation, apoptosis, and glucose metabolism. Among its many roles, Akt appears to be common to signaling pathways that mediate the metabolic effects of insulin in several physiologically important target tissues [, ]. Human Akt has three isoforms derived for distinct genes: Akt1/PKBalpha, Akt2/PKBbeta, and Akt3/PKBgamma.This entry represents Akt3 from mammals and related proteins. Akt3 inhibits adipogenesis via WNK1/SGK1 signaling []. It is not required for the maintenance of normal carbohydrate metabolism but is essential for the attainment of normal brain size [].
Zinc finger proteins 608 and 609 (ZNF608/ZNF609) are putative transcription factors. ZNF608 represses the expression of ZNF609, which in turn represses recombination-activating gene 1 (Rag1) and Rag2 expression in thymocytes []. Interestingly, ZNF609 generates circular RNA (Cir-ZNF609), a novel kind of noncoding RNA that form loop structures without 5'-3' polarities and polyadenylated tails. Cir-ZNF609 has been found to regulate myoblast proliferation and AKT3 expression [, ]. Cir-ZNF609 has also been linked to vascular endothelial dysfunction [].
