Role of phosphorylation in p53 acetylation and PAb421 epitope recognition in baculoviral and mammalian expressed proteins.

Post-translational modifications, such as phosphorylation and acetylation of the tumour suppressor protein p53, elicit important effects on the function and the stability of the resultant protein. However, as phosphorylation and acetylation are dynamic events subject to complex controls, elucidating the relationships between phosphorylation and acetylation is difficult.In the present study we sought to address this problem by comparing full-length wild-type p53 with full-length p53 proteins mutated at specific phosphorylation targets. Recombinant murine p53 proteins were expressed in insect cells (using the baculoviral expression vector system) and in a mammalianin vitrotranscription/translation reticulocyte lysate system. In p53 proteins derived from baculoviral expression vectors, S37A (but not S37D) was found to abrogate phosphorylation at S15. Lysine 382 (K382) is constitutively acetylated and was shown to form part of the epitope recognized by PAb421. Lysine 373 (K373) was only acetylated following substitutions at S315 (S315A or S315D) or at S378 (S378A). Importantly, in baculoviral expressed proteins, PAb421 reactivity was independent of K373 acetylation status, indicating that acetylation at K382 specifically determines the PAb421 epitope. [ABSTRACT FROM AUTHOR]

Copyright of FEBS Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)