Modulation of c-Myb-induced transcription activation by a phosphorylation site near the negative regulatory domain.

• DOI: 10.1073/pnas.92.14.6429
• Publication Date: 2006-05-31T13:14:14Z
• Authors: N Aziz; M R Miglarese; R C Hendrickson; J Shabanowitz; T W Sturgill; D F Hunt; T P Bender
• Keywords: MYB

The c-myb protooncogene encodes a highly conserved transcription factor that functions as both an activator and repressor of transcription. v-myb oncogenes E26 leukemia virus avian myeloblastosis encode proteins are truncated at the amino carboxyl terminus, deleting portions c-Myb DNA-binding negative regulatory domains. This has led to speculation deleted regions contain important sequences. We previously reported 42-kDa mitogen-activated protein kinase (p42mapk) phosphorylates chicken murine multiple sites in domain vitro, suggesting phosphorylation might provide mechanism regulate function. now report three tryptic phosphopeptides derived from vitro phosphorylated comigrate with metabolically labeled immunoprecipitated erythroleukemia cells. At least two these peptides on serine-528. Replacement serine-528 alanine results 2- 7-fold increase ability transactivate Myb-responsive promoter/reporter gene construct. These findings suggest serves activity loss this site v-Myb may contribute their transforming potential.