Nef
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nef
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HIV-1 Nef induces cyclin K interaction with CDK9, which contributes to the inhibition of CDK9 nuclear translocation |
PubMed
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nef
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CDK9 mRNA and kinase activity are upregulated in HIV-1 Nef-expressing human T cell lines |
PubMed
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nef
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HIV-1 Nef interacts with Hsp40, leading to increased Hsp40 translocation to the nucleus of infected cells and facilitation of viral gene expression by complex formation of Hsp40 with the cdk9-associated transcription complex |
PubMed
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Tat
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tat
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HIV-1 Tat binds to CDK9 and CCNT1 (CycT1) in an additive manner as shown through Fluoppi (fluorescent-based technology detecting protein-protein interactions) |
PubMed
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tat
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The N-terminus (amino acids 1-48, including activation domain) of HIV-1 Tat binds to P-TEFb through a direct interaction with the N-terminus (amino acids 1-290) of cyclin T1 during Tat-mediated transactivation of the HIV-1 LTR promoter |
PubMed
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tat
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Binding of HIV-1 Tat to CDK9 stabilizes hydrogen bonds between ATP and residues Lys48, Asp104, and Cys106 and facilitates the salt bridge network pertaining to the phosphorylated Thr186 at the activation loop |
PubMed
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tat
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HIV-1 Tat competes with HEXIM1 for binding to 7SK RNA and inhibits the formation of the P-TEFb-HEXIM1-7SK complex. Tat binds to nucleotides 10-48 of 7SK RNA |
PubMed
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tat
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A La-related protein, LARP7, is associated with P-TEFb, HEXIM1/2, MEPCE, and 7SK RNA in a large stable complex form. Knockdown of LARP7 decreases the steady-state level of 7SK, but increases free P-TEFb and enhances Tat-mediated transcription |
PubMed
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tat
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HIV-1 Tat forms at least two distinct P-TEFb-containing complexes. Tatcom1 is composed of P-TEFb, AF9, ENL, ELL, AFF1, AFF4, and PAF1, presenting strong CTD-kinase activity, while Tatcom2 consists of 7SK, LARP7, and MEPCE with two molecules of Tat/P-TEFb |
PubMed
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tat
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HIV-1 Tat recruits P-TEFb to the HIV-1 Transcription Activation Response (TAR) RNA during Tat-mediated transactivation of the HIV-1 LTR promoter |
PubMed
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tat
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P-TEFb interacts with HIV-1 Tat as part of both the HIV-1 transcription preinitiation and elongation complexes |
PubMed
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tat
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Cyclin-dependent kinase 9 (CDK9, CDC2-related kinase) is identified to interact with HIV-1 Tat mutant Nullbasic in HeLa cells by LC MS/MS |
PubMed
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tat
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A homogeneous assay in AlphaLISA indicates that the affinity between HIV-1 Tat and pTEFb is determined to be approximately 20pM, and only 7% of purified Tat is found to be active in forming tertiary complex with pTEFb |
PubMed
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tat
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AFF1 enhances the affinity of HIV-1 Tat for CycT1, which competitively dissociates HEXIM1 and is responsible for AFF1's promotion of Tat's extraction of CDK9/CycT1 from 7SK snRNP |
PubMed
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tat
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HIV-1 Tat increases the amount of ELL2 bound to P-TEFb without affecting the AFF4-P-TEFb binding. CDK9 is required for the Tat-induced ELL2 accumulation and Tat interaction with ELL2 |
PubMed
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tat
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The interaction of HIV-1 Tat with HIV-1 Transcription Activation Response (TAR) RNA is enhanced by the interaction of Tat with P-TEFb, and TAR RNA also enhances the interaction between Tat and cyclin T1 |
PubMed
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tat
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P-TEFb is required for HIV-1 Tat-mediated transcriptional activation |
PubMed
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tat
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During HIV-1 Tat mediated transactivation of the HIV-1 LTR promoter, Tat stimulates the phosphorylation of the C-terminal domain (CTD) of RNA polymerase II by P-TEFb, leading to transcription elongation |
PubMed
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tat
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ZASC1, a cellular transcription factor, interacts with HIV-1 Tat and cellular proteins CDK9/Cyclin T1 (P-TEFb) in a TAR-independent manner, suggesting that the Tat/P-TEFb complex in the transcriptional elongation site is promoted by ZASC1 |
PubMed
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tat
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Small molecule ligands disrupt the CDK9/Cyclin T1/Tat complex and dissociate CDK9 away from the HIV-1 transcription complex |
PubMed
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tat
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The Tat-AFF4-P-TEFb complex containing HIV-1 Tat (residues 1-48), human Cyclin T1 (residues 1-266), human Cdk9 (residues 7-332), and human AFF4 (residues 27-69) is determined by the crystal structure analysis |
PubMed
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tat
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HIV-1 Tat recruits PPM1G phosphatase protein to dephosphorylate the T loop of CDK9 and release P-TEFb from the 7SK snRNP complex |
PubMed
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tat
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Binding of isolated AFF1(1-308) CBS to CDK9/CycT1 prevents HIV-1 Tat from activating HIV transcription and assembling complete SECs (AFF1, AFF4, ELL2, and ENL). The AFF1(1-308) M60A/L61A mutant shows no suppression of Tat transactivation |
PubMed
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tat
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The interaction of HIV-1 Tat with cellular transcription factors CDK9 and Sp1 is required for Tat activation of MAP2K3-, MAP2K6-, and IRF7-mediated luciferase transcription |
PubMed
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tat
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The interaction of Tip110 with HIV-1 Tat and the RNAPII C-terminal domain leads to the recruitment of increased CDK9/CycT1 to the transcription complex |
PubMed
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tat
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CDK9-CycT1-AFF1 is stimulated by HIV-1 Tat and transferred as a single complex unit to BRD4 upon stress-induced disruption of AFF1-containing 7SK snRNP (HEXIM1, MEPCE, LARP7, 7SK RNA, CDK9, CycT1, and AFF1) |
PubMed
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tat
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Phosphorylation of CDK9 at position Ser175 regulates the competition between HIV-1 Tat and BRD4 for P-TEFb binding |
PubMed
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tat
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JQ1, a small molecule inhibitor of Brd4, increases CDK9 T-loop phosphorylation in Tat-dependent manner and partially dissociates P-TEFb from 7SK snRNP in Jurkat cells |
PubMed
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tat
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Brd4 inhibits HIV-1 Tat-human super elongation complex (components AFF4, ELL2, CycT1, and CDK9) by competing with HIV-1 Tat for binding to P-TEFb on HIV-1 promoter |
PubMed
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tat
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CDK2 regulates HIV-1 Tat-mediated transcription by phosphorylation of CDK9 at position Ser90 and decreases 7SK RNA levels |
PubMed
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tat
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HIV-1 Tat mutations at positions Y26 and K28 show the most defect in the Tat:TAR:P-TEFb complex formation, but Tat:P-TEFb assembly is not abolished |
PubMed
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tat
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HIV-1 Tat mutations at positions P3, P6, W11, K12, T20, T23, V36, I39, T40, and Y47 show decreased Tat activity and P-TEFb assembly/Cdk9 activation, with three residues P3, P6, and W11 possibly involved in Cdk9 interactions |
PubMed
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tat
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Coexpression of RNA-binding domain deficient Tat (T-RS) and two fusion proteins CycT1N-Rev and Cdk9-Rev synergistically stimulates transcription when P-TEFb is tethered to RNA through Rev, and thus T-RS is no longer as an inhibitor |
PubMed
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tat
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An RNA-binding domain deficient Tat excludes wild-type Tat from the promoter by preferentially assembling with P-TEFb through the Tat activation domain, but can not facilitate transfer of P-TEFb to TAR, thus blocking transition to elongation |
PubMed
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tat
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HIV-1 Tat-mediated release of P-TEFb from the 7SK sn RNP results in a conformational change in 7SK RNA and release of HEXIM1 from the complex |
PubMed
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tat
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TAR binds Tat and P-TEFb as it emerges on the nascent transcript, competitively displacing the inhibitory 7SK snRNP (HEXIM1 and LARP7) and activating the P-TEFb kinase |
PubMed
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tat
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HIV-1 Tat stimulates the phosphorylation of SPT5 by P-TEFb during transactivation of the HIV-1 LTR promoter |
PubMed
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tat
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HIV-1 Tat-mediated stimulation of RNA polymerase II C-terminal domain phosphorylation by P-TEFb leads to stimulation of co-transcriptional capping of HIV-1 mRNA |
PubMed
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tat
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Inhibition of Ca(2+) signaling leads to dephosphorylation of Thr186 on CDK9, which results in the decreased transactivation of the HIV-1 LTR by HIV-1 Tat |
PubMed
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tat
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ATP analogs are effective inhibitors of HIV-1 Tat-mediated activated transcription with a decreased loading of CDK9 onto the HIV-1 DNA |
PubMed
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tat
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HIV-1 Q35L mutant fails to efficiently bind either CDK9 or CycT1 resulting in the defective gene expression. However, the I39Q mutation rescues the Q35L mutant's loss of function |
PubMed
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tat
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SKIP is required for Tat transactivation in vivo and stimulates HIV-1 transcription elongation by associating with CycT1:CDK9 (P-TEFb) and Tat:P-TEFb complexes both in nuclear extracts and in recombinant Tat:P-TEFb:TAR RNA complexes in vitro |
PubMed
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tat
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HIV-1 Tat and P-TEFb undergo constant association and dissociation cycles with TAR and the elongating polymerase in living cells |
PubMed
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tat
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Tat-C/EBPbeta association is mediated through cdk9, which phosphorylates C/EBPbeta. C/EBPbeta-cyclin T1 association requires the presence of cdk9 |
PubMed
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tat
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HIV-1 infection leads to activation of P-TEFb due to HIV-1 Tat-mediated release of P-TEFb from the large form |
PubMed
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tat
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The P-TEFb binding region (amino acids 1209-1362) of BRD4 is required for HIV-1 Tat-mediated release of P-TEFb from the 7SK snRNP |
PubMed
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tat
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CDK11 depletion reduces protein expression of CDK9 and HEXIM1 and Tat transactivation of HIV-1 provirus |
PubMed
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tat
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Acetylation of HIV-1 Tat by cellular histone acetyltransferases regulates the binding of Tat to P-TEFb |
PubMed
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tat
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Mutant CycT1 protein containing triple T-to-A mutations in the N-terminal region (amino acids T143, T149, and T155) associates with CDK9 and HIV-1 Tat as a kinase-negative complex and blocks HIV transactivation |
PubMed
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tat
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The human I-mfa domain-containing protein (HIC) interacts with both P-TEFb and HIV-1 Tat, and modulates Tat transactivation of the HIV-1 LTR promoter |
PubMed
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tat
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Cyclin T1 is capable of recruiting CDK9 and HIV-1 Tat to splicing factor-rich nuclear speckle regions, suggesting nuclear speckles are a site of P-TEFb and Tat function |
PubMed
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tat
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The up and downregulation of expression of CDK9 and cyclin T1 or sequestration of cyclin T1 in infected cells may regulate HIV-1 latency by up or downregulating HIV-1 Tat transcriptional activation |
PubMed
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tat
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Amino acids 260-263 of cyclin T1 are critical for HIV-1 Tat-mediated transcriptional activation, and mediate the species specificity of cyclin T1 and P-TEFb binding to Tat |
PubMed
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tat
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P-TEFb regulates HIV-1 Tat-mediated activation of transcription through two built-in auto inhibitory mechanisms, autophosphorylation of CDK9 and cyclin T1 binding to the transcription elongation factor Tat-SF1 |
PubMed
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tat
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Undetectable CycT1 protein and un-phosphorylation of CDK9 in undifferentiated monocytes result in the lack of Tat transactivation of the LTR promoter in early viral life cycle |
PubMed
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tat
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Interaction of P-TEFb with histone H1 results in its phosphorylation at position Ser-183 in a Tat-dependent manner, which is necessary for transcription from the HIV-1 LTR |
PubMed
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tat
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CDK9 is involved in Tat-induced MCP-1/CCL2 gene expression in human astrocytes |
PubMed
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tat
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PARP1 negatively regulates HIV-1 transcription by directly competing with Tat-P-TEFb complex for binding to TAR RNA |
PubMed
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tat
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HIV-1 Tat-induced kinase activity of P-TEFb is highly sensitive to flavopiridol, a CDK inhibitor. P-TEFb-mediated phosphorylation of RNAP II CTD, SPT5, and Tat-SF1 during HIV-1 transcription elongation is also highly sensitive to flavopiridol |
PubMed
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tat
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The p160 nuclear receptor co-activator GRIP1 binds to the N-terminal region of HIV-1 Tat, bridging HIV-1 LTR promoter-bound factors to the Tat-P-TEFb complex and enhancing the transactivating activity of Tat |
PubMed
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tat
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Cdk9, the catalytic subunit of P-TEFb, is ubiquitinated by Skp1/Cul1/F-box protein E3 ubiquitin ligase Skp2, which facilitates the formation of the RNA-protein complex between P-TEFb, Tat, and TAR, thereby enhancing Tat transactivation |
PubMed
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tat
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The growth factor granulin and the promyelocytic leukemia (PML) protein regulate HIV-1 Tat-mediated transcriptional activation by competing with the Tat interaction with cyclin T1/P-TEFb |
PubMed
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tat
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TFIIH inhibits the phosphorylation of CDK9 in the HIV-1 transcription preinitiation complex, while HIV-1 Tat stimulates CDK9 autophosphorylation to activate transcription elongation |
PubMed
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tat
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Overexpression of CDK9 or CDK9 mutants inhibits HIV-1 Tat transcriptional activation |
PubMed
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tat
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Tat-SF1 is a required cofactor for HIV-1 Tat activity that complexes with P-TEFb and Tat, and stimulates Tat-mediated activation of the HIV-1 LTR promoter |
PubMed
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tat
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P-TEFb, Puralpha and HIV-1 Tat cooperate to activate the TNFalpha promoter |
PubMed
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tat
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Hsp70 and Hsp90/Cdc37 stabilize CDK9 as well as the assembly of an active P-TEFb complex which is stimulated by HIV-1 Tat during HIV-1 transcriptional activation |
PubMed
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tat
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HIV-1 Tat competes with CIITA for the binding to P-TEFb, leading to the downregulation of MHC class II gene expression |
PubMed
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tat
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MAQ1 and 7SK RNA interact with P-TEFb and compete with the binding of HIV-1 Tat to cyclin T1, suggesting the TAR RNA/Tat lentivirus system evolved to subvert the cellular 7SK RNA/MAQ1 system |
PubMed
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Vif
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vif
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HIV-1 Vif interacts with CDK9 to regulate Vif-mediated G1-to-S transition and siRNA against CDK9 counteracts the transition |
PubMed
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Vpr
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vpr
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HIV-1 Vpr interacts with CDK9 through binding to HIV-1 Tat and cyclin T1 in a ternary complex, Tat-Vpr-Cyclin T1-CDK9, and enhances Tat transactivation of the viral LTR promoter |
PubMed
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