Identification of protein kinase A catalytic subunit β as a novel binding partner of p73 and regulation of p73 function
Identification of protein kinase A catalytic subunit β as a novel binding partner of p73 and regulation of p73 function
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DOI：
10.1074/jbc.m414323200
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发表时间：
2005-04-29
影响因子：
4.8
通讯作者：
Nakagawara, A
中科院分区：
文献类型：
--
作者：
Hanamoto, T;Ozaki, T;Nakagawara, A
Post-translational modifications play a crucial role in regulation of the protein stability and pro-apoptotic function of p53 as well as its close relative p73. Using a yeast two-hybrid screening based on the Sos recruitment system, we identified protein kinase A catalytic subunit beta (PKA-C beta) as a novel binding partner of p73. Co-immunoprecipitation and glutathione S-transferase pull-down assays revealed that p73 alpha associated with PKA-C beta in mammalian cells and that their interaction was mediated by both the N- and C-terminal regions of p73 alpha. In contrast, p53 failed to bind to PKA-C beta. In vitro phosphorylation assay demonstrated that glutathione S-transferase-p73 alpha- ( 1 - 130), which has one putative PKA phosphorylation site, was phosphorylated by PKA. Enforced expression of PKA-C beta resulted in significant inhibition of the transactivation function and pro-apoptotic activity of p73 alpha, whereas a kinase-deficient mutant of PKA-C beta had no detectable effect. Consistent with this notion, treatment with H-89 ( an ATP analog that functions as a PKA inhibitor) reversed the dibutyryl cAMP-mediated inhibition of p73 alpha. Of particular interest, PKA-C beta facilitated the intramolecular interaction of p73 alpha, thereby masking the N- terminal transactivation domain with the C-terminal inhibitory domain. Thus, our findings indicate a PKA-C beta-mediated inhibitory mechanism of p73 function.
