protein HEXIM1 (hexamethylene bis-acetamide-inducible protein 1, cardiac lineage protein 1, estrogen down-regulated gene 1 protein, Menage a quatre protein 1, HEXIM1, CLP1, EDG1, HIS1, MAQ1)
Jump to navigation
Jump to search
Function
- transcriptional regulator
- functions as a general RNA polymerase 2 transcription inhibitor
- in cooperation with 7SK snRNA sequesters P-TEFb in a large inactive 7SK snRNP complex preventing RNA polymerase 2 phosphorylation & subsequent transcriptional elongation
- may also regulate NF-kappa-B, ESR1, NR3C1 & CIITA-dependent transcriptional activity
- homooligomer & heterooligomer with HEXIM2, probably dimeric
- component of the 7SK snRNP complex
- interacts with the N-CoR complex through NCOR1
- interacts with ESR1 & NR3C1
- mayinteract with NF-kappa-B through RELA
Structure
- coiled-coil domain mediates oligomerization
- belongs to the HEXIM family
Compartment
Expression
- ubiquitously expressed
- higher expression in placenta
- HEXIM1 & HEXIM2 are differentially expressed
- expressed in endocrine tissues
- up-regulated by HMBA (hexamethylene bisacetamide) (at protein level)
- down-regulated by estrogen
Pathology
- inhibits Tat activity which is required for HIV-1 transcription