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Direct activation of protein phosphatase‐2A 0 by HIV‐1 encoded protein complex NCp7:vpr
Author(s) -
Tung H.Y.Lim,
De Rocquigny Hughes,
Zhao Ling-Jun,
Cayla Xavier,
Roques Bernard P,
Ozon René
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(96)01470-6
Subject(s) - human immunodeficiency virus (hiv) , phosphatase , virology , chemistry , computational biology , biology , biochemistry , enzyme
The effects of HIV‐1 encoded proteins NCp7, vpr and NCp7:vpr complex on the activity of protein phosphatase‐2A 0 have been tested. We report that NCp7 is an activator of protein phosphatase‐2A 0 and that vpr activated protein phosphatase‐2A 0 only slightly. We also report that NCp7 and vpr form a tight complex which becomes a more potent activator of protein phosphatase‐2A 0 than NCp7 alone. The ability of NCp7 to activate protein phosphatase‐2A 0 is regulated by vpr. The C‐terminal portion of vpr prevents NCp7 from activating protein phosphatase‐2A 0 while the N‐terminal portion of vpr potentiates the effect of NCp7 on the activity of protein phosphatase‐2A 0 . Our findings indicate that vpr may be acting as a targeting subunit which directs NCp7 to activate protein phosphatase‐2A 0 . In view of the fact that protein phosphatase‐2A functions as an inhibitor of G 2 to M transition of the cell cycle and is involved in other key cellular processes such as the control of RNA transcription, the results presented in this report may explain how HIV‐1 causes cell cycle arrest which may lead to CD 4+ T cell depletion and also how it disturbs normal cellular processes of its host cell.