Steroid receptor coactivators (SRCs) exert profound effects on animal development and physiology. Genetic ablation experiments indicate that various SRC proteins might have differential physiological roles; however, clear evidence of functional specificity has not yet been shown at the molecular level. Here we report the identification of a new SRC1 interacting protein, glutamate-rich coactivator interacting with SRC1 (GAS), which contains a central glutamate-rich region and has transactivation activity. Interestingly, GAS interacts only with SRC1, and not with glucocorticoid receptor interacting protein 1 (GRIP1) or amplified in breast cancer 1 (AIB1), the other two members of the SRC family. It interacts with oestrogen receptor-α (ERα) and participates in both oestrogen receptor-regulated gene transcription and oestrogen-stimulated G1/S cell-cycle transition. Our data thus indicate that GAS is a new transcription cofactor and that different SRCs are associated with distinct secondary cofactors.
ASJC Scopus subject areas
- Molecular Biology