Protein kinase B (Akt) is a Ser/Thr kinase,which in mammals comprise three highly homologous members known as PKBα/Akt1,PKBβ/Akt2 and PKBγ/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.
Src is a non-receptor protein tyrosine kinase activated by a number of extracellular signal moleculars. It is recruited to peripheral sites through myristoylation and the SH3 domain. Src initiates intracellular signal trandsduction pathways that influence cell adhesion, migration, growth, differentiation and survival though catalytic domain. Src is normally maintained in an inactive conformation because of carboxy terminal Src kinase, but can be activated transiently during cellular events such as mitosis or constitutively by abnormal events such as mutation and some cancers. In additions, c-Src protein is found to be highly activated and the Src gene is frequently over-expressed in many cancers. These findings suggest that the relationship between c-Src activation/over-expression and cancer progression appears to be significant.
