Reaction: Hyperphosphorylation (Ser2) of RNA Pol II CTD by the P-TEFb(Cyclin T1:Cdk9) complex
The association between Tat, TAR and P-TEFb is believed to bring the catalytic subunit of P-TEFb(Cyclin T1:Cdk9) in close proximity to Pol II where it hyperphosphorylates the CTD of Pol II (Herrmann et al., 1995; Zhou et al. 2000). In the presence of Tat, P-TEFb(Cyclin T1:CDK9) has been shown to phosphorylate serine 5 in addition to serine 2 suggesting that modification of the substrate specificity of CDK9 may play a role in the ability of Tat to promote transcriptional elongation (Zhou et al. 2000).
Reaction - small molecule participants:
ADP [nucleoplasm]
ATP [nucleoplasm]
Reactome.org reaction link: R-HSA-167191
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Reaction input - small molecules:
ATP(4-)
Reaction output - small molecules:
ADP(3-)
Reactome.org link: R-HSA-167191