2v0p | pdb_00002v0p
THE STRUCTURE OF TAP42 ALPHA4 SUBUNIT
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Overview
Physiological functions of protein phosphatase 2A (PP2A) are determined via the association of its catalytic subunit (PP2Ac) with diverse regulatory subunits. The predominant form of PP2Ac assembles into a heterotrimer comprising the scaffolding PR65/A subunit together with a variable regulatory B subunit. A distinct population of PP2Ac associates with the Tap42/alpha4 subunit, an interaction mutually exclusive with that of PR65/A. Tap42/alpha4 is also an interacting subunit of the PP2Ac-related phosphatases, PP4 and PP6. Tap42/alpha4, an essential protein in yeast and suppressor of apoptosis in mammals, contributes to critical cellular functions including the Tor signaling pathway. Here, we describe the crystal structure of the PP2Ac-interaction domain of Saccharomyces cerevisiae Tap42. The structure reveals an all alpha-helical protein with striking similarity to 14-3-3 and tetratricopeptide repeat (TPR) proteins. Mutational analyses of structurally conserved regions of Tap42/alpha4 identified a positively charged region critical for its interactions with PP2Ac. We propose a scaffolding function for Tap42/alpha4 whereby the interaction of PP2Ac at its N-terminus promotes the dephosphorylation of substrates recruited to the C-terminal region of the molecule.
About this Structure
2V0P is a Single protein structure of sequence from Saccharomyces cerevisiae with ZN as ligand. Full crystallographic information is available from OCA.
Reference
The structure of Tap42/alpha4 reveals a tetratricopeptide repeat-like fold and provides insights into PP2A regulation., Yang J, Roe SM, Prickett TD, Brautigan DL, Barford D, Biochemistry. 2007 Jul 31;46(30):8807-15. Epub 2007 Jul 6. PMID:17616149
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