Human protein: AF4/FMR2 family member 4
Human protein sequence: MNREDRNVLRMKERERRNQEIQQGEDAFPPSSPLFAEPYKVTSKEDKLSSRIQSMLGNYDEMKDFIGDRSIPKLVAIPKPTVPPSADEKSNPNFFEQRHGGSHQSSKWTPVGPAPSTSQSQKRSSGLQSGHSSQRTSAGSSSGTNSSGQRHDRESYNNSGSSSRKKGQHGSEHSKSRSSSPGKPQAVSSLNSSHSRSHGNDHHSKEHQRSKSPRDPDANWDSPSRVPFSSGQHSTQSFPPSLMSKSNSMLQKPTAYVRPMDGQESMEPKLSSEHYSSQSHGNSMTELKPSSKAHLTKLKIPSQPLDASASGDVSCVDEILKEMTHSWPPPLTAIHTPCKTEPSKFPFPTKESQQSNFGTGEQKRYNPSKTSNGHQSKSMLKDDLKLSSSEDSDGEQDCDKTMPRSTPGSNSEPSHHNSEGADNSRDDSSSHSGSESSSGSDSESESSSSDSEANEPSQSASPEPEPPPTNKWQLDNWLNKVNPHKVSPASSVDSNIPSSQGYKKEGREQGTGNSYTDTSGPKETSSATPGRDSKTIQKGSESGRGRQKSPAQSDSTTQRRTVGKKQPKKAEKAAAEEPRGGLKIESETPVDLASSMPSSRHKAATKGSRKPNIKKESKSSPRPTAEKKKYKSTSKSSQKSREIIETDTSSSDSDESESLPPSSQTPKYPESNRTPVKPSSVEEEDSFFRQRMFSPMEEKELLSPLSEPDDRYPLIVKIDLNLLTRIPGKPYKETEPPKGEKKNVPEKHTREAQKQASEKVSNKGKRKHKNEDDNRASESKKPKTEDKNSAGHKPSSNRESSKQSAAKEKDLLPSPAGPVPSKDPKTEHGSRKRTISQSSSLKSSSNSNKETSGSSKNSSSTSKQKKTEGKTSSSSKEVKEKAPSSSSNCPPSAPTLDSSKPRRTKLVFDDRNYSADHYLQEAKKLKHNADALSDRFEKAVYYLDAVVSFIECGNALEKNAQESKSPFPMYSETVDLIKYTMKLKNYLAPDATAADKRLTVLCLRCESLLYLRLFKLKKENALKYSKTLTEHLKNSYNNSQAPSPGLGSKAVGMPSPVSPKLSPGNSGNYSSGASSASASGSSVTIPQKIHQMAASYVQVTSNFLYATEIWDQAEQLSKEQKEFFAELDKVMGPLIFNASIMTDLVRYTRQGLHWLRQDAKLIS

HIV protein: Tat
Interaction type: complexes with
Description: 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
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE

HIV protein: Tat
Interaction type: complexes with
Description: 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
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE

HIV protein: Tat
Interaction type: interacts with
Description: HIV-1 Tat is identified to have a physical interaction with AF4/FMR2 family, member 4 (AFF4) in human HEK293 and/or Jurkat cell lines by using affinity tagging and purification mass spectrometry analyses
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE

HIV protein: Tat
Interaction type: competes with
Description: 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
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE

HIV protein: Tat
Interaction type: binds
Description: HIV-1 Tat binds adjacent to AFF4, increases the affinity of AFF4 for P-TEFb, and rescues P-TEFb binding to AFF4 interface mutants. The AFF4 G61A/M62A mutant abolishes this rescue
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE

HIV protein: Tat
Interaction type: induces complex with
Description: 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
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE

HIV protein: Tat
Interaction type: complexes with
Description: 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
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE

HIV protein: Tat
Interaction type: interacts with
Description: The crystal structure demonstrates that Met55Thr substitution in AFF4 forms a hydrogen bond with Glu246 of Cyclin T1, which is not as favorable for HIV-1 Tat docking
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE

HIV protein: Tat
Interaction type: mediated by
Description: HIV-1 Tat transactivation is mediated by the AFF4- super elongation complex but does so less than the AFF4-super elongation complex due to a single amino acid that causes a change in affinity of Tat for cyclin T1
HIV protein sequence: MEPVDPRLEPWKHPGSQPKTACTNCYCKKCCFHCQVCFITKALGISYGRKKRRQRRRAHQNSQTHQASLSKQPTSQPRGDPTGPKE