Protein kinase B (Akt) is a Ser/Thr kinase,which in mammals comprise three highly homologous members known as PKB?/Akt1,PKB?/Akt2 and PKB?/Akt3. PKB is activated by hormones?growth factor and extra cellular matrix. The activation occurs downstream of PI3K. PKB phosphorylates and regulates the function of many cellular protein involved in processes that include survival,apoptosis, proliferation,glycogen metabolism and cancer progression. Although many mechanisms remains to be fully characterized,the research of PKB is thought to have a useful profect.