A novel and essential mechanism determining specificity and activity of protein phosphatase 2A (PP2A) in vivo

被引:87
作者
Fellner, T [1 ]
Lackner, DH [1 ]
Hombauer, H [1 ]
Piribauer, P [1 ]
Mudrak, I [1 ]
Zaragoza, K [1 ]
Juno, C [1 ]
Ogris, E [1 ]
机构
[1] Univ Vienna, Vienna Bioctr, Inst Med Biochem, Div Mol Biol, A-1030 Vienna, Austria
关键词
PP2A biogenesis; PTPA; metals; active site;
D O I
10.1101/gad.259903
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
Protein phosphatase 2A (PP2A) is an essential intracellular serine/threonine phosphatase containing a catalytic subunit that possesses the potential to dephosphorylate promiscuously tyrosine-phosphorylated substrates in vitro. How PP2A acquires its intracellular specificity and activity for serine/threonine-phosphorylated substrates is unknown. Here, we report a novel and phylogenetically conserved mechanism to generate active phospho-serine/threonine-specific PP2A in vivo. Phosphotyrosyl phosphatase activator (PTPA), a protein of so far unknown intracellular function, is required for the biogenesis of active and specific PP2A. Deletion of the yeast PTPA homologs generated a PP2A catalytic subunit with a conformation different from the wild-type enzyme, as indicated by its altered substrate specificity, reduced protein stability, and metal dependence. Complementation and RNA-interference experiments showed that PTPA fulfills an essential function conserved from yeast to man.
引用
收藏
页码:2138 / 2150
页数:13
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