Yeast Two Hybrid of MST1 and Its Association with Salvador

Mammalian STE20-like 1 is a Ser/Thr kinase,which can be activated by caspase 3,leading to DNA fragmentation,membrane blebbing and resulting in chromatin condensation by phosphoralating H2B.Salvador can lead to cell apoptosis and cell cycle exit in Drosophila system,but the function of apoptosis and its signal pathway are not found in mammalian cells.In this work,22 fragments of(Salvador) were obtained from mouse embryo library using MST1 as a bait in yeast two-hybrid system.By (using) the purified 6His-MST1 and GST-Salvador expressed by E.coli,it was further demonstrated that these two proteins can associate with each other in vitro.In addition,MST1 cannot phosphorylate Salvador in vitro,but Salvador can strongly inhibit the phosphorylation of monobuthlphosphate(MBP) catalysed by MST1,suggesting Salvador is likely to participate MST1 induced apoptosis process by influencing MST1 kinase activity.