Molecular Identification of I1PP2A, a Novel Potent Heat-Stable Inhibitor Protein of Protein Phosphatase 2A

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• 作者：Mei Li ; Anthony Makkinje ; and Zahi Damuni
• 刊名：Biochemistry
• 出版年：1996
• 出版时间：June 4, 1996
• 年：1996
• 卷：35
• 期：22
• 页码：6998 - 7002
• 全文大小：270K
• 年卷期：v.35,no.22(June 4, 1996)
• ISSN：1520-4995

文摘

The amino acid sequences of two tryptic peptides derived frompurified preparations of I₁^PP2Aindicated that this potent heat-stable protein inhibitor of proteinphosphatase 2A (PP2A) may be equivalentto putative histocompatibility leukocyte antigens class II-associatedprotein I (PHAP-I). Experimentsusing purified preparations of recombinant human PHAP-I confirmed thatthis protein inhibited PP2A.Half-maximal inhibition of the phosphatase occurred at about 4 nMPHAP-I, similar to the half-maximalinhibition obtained with purified preparations of bovine kidneyI₁^PP2A. In addition, PHAP-I did notaffectthe activities of protein phosphatase 1, 2B, and 2C in a manneranalogous to that of I₁^PP2A. Together,theresults establish the identity of I₁^PP2A on afirm basis.