Phosphorylation of MDM2 at serine-395 by ATM kinase Phosphorylation of p53 at ser-15 by ATM kinase PathwayStep4448 PathwayStep4447 PathwayStep4454 Stabilization of p53 Edited: Matthews, L, 2008-05-12 13:48:33 Later studies pin-pointed that a single serine (Ser-15) was phosphorylated by ATM and phosphorylation of Ser-15 was rapidly-induced in IR-treated cells and this response was ATM-dependent (Canman et al, 1998; Banin et al, 1998 and Khanna et al, 1998). ATM also regulates the phosphorylation of p53 at other sites, especially Ser-20, by activating other serine/threonine kinases in response to IR (Chehab et al, 2000; Shieh et al, 2000; Hirao et al 2000). Phosphorylation of p53 at Ser-20 interferes with p53-MDM2 interaction. MDM2 is transcriptionally activated by p53 and is a negative regulator of p53 that targets it for degradation (Haupt et al, 1997; Kubbutat et al, 1997). In addition modification of MDM2 by ATM also affects p53 stabilization (Maya et al, 2001). Pubmed10673500 Pubmed10673501 Pubmed10710310 Pubmed11331603 Reactome Database ID Release 4369541 Reactome, http://www.reactome.org ReactomeREACT_309 Reviewed: Sanchez, Y, 2008-05-07 22:09:03 Autodegradation of the E3 ubiquitin ligase COP1