since mhc ( major histocompatibility complex ) class i molecules are known to contain phosphorylation sites in their c-terminal intracellular domain , we have studied the regulation of hla ( human leucocyte antigen ) phosphorylation in intact cells by two mitogens , namely tpa ( 12-o-tetradecanoylphorbol 13-acetate ) , a phorbol ester , and insulin , which are thought to exert their mitogenic effects through the stimulation of different protein kinases ( protein kinase c and a tyrosine kinase respectively ) .
C0031715
phosphorylation
C0033640
protein kinases