Dephosphorylation of CDK9 by protein phosphatase 2A and protein phosphatase-1 in Tat-activated HIV-1 transcription.

ABSTRACT:

Background

HIV-1 Tat protein recruits human positive transcription elongation factor P-TEFb, consisting of CDK9 and cyclin T1, to HIV-1 transactivation response (TAR) RNA. CDK9 is maintained in dephosphorylated state by TFIIH and undergo phosphorylation upon the dissociation of TFIIH. Thus, dephosphorylation of CDK9 prior to its association with HIV-1 preinitiation complex might be important for HIV-1 transcription. Others and we previously showed that protein phosphatase-2A and protein phosphatase-1 regulates HIV-1 transcription. In the present study we analyze relative contribution of PP2A and PP1 to dephosphorylation of CDK9 and to HIV-1 transcription in vitro and in vivo.

Results

In vitro, PP2A but not PP1 dephosphorylated autophosphorylated CDK9 and reduced complex form

SUBMITTER: Ammosova T 

PROVIDER: S-EPMC1187922 | biostudies-literature | 2005 Jul

REPOSITORIES: biostudies-literature