The molecular basis of the interaction between the proline-rich SH3-binding motif of PNRC and estrogen receptor alpha.
PNRC and PNRC2 are members of a new family of nuclear receptor coactivators. We systematically determined the molecular basis and the structure/function relationship for the PNRC-ERalpha interaction. PNRC was found to interact with ERalpha mainly through its C-terminus region, amino acids 270-327, and an SH3-binding motif within this region was shown to be essential for PNRC to interact with and function as coactivator of ERalpha. The importance of the flanking sequences of SH3-binding motif in the interaction between PNRC and ERalpha was also investigated. The PNRC-interacting domain(s) on ERalpha was also mapped. PNRC was found to interact with both AF1 and LBD of ERalpha, and to function as a coactivator for both AF1 and AF2 transactivation functions. The interaction of ERalpha mutants, I358R, K362A, V376R, L539R and E542K, with PNRC/PNRC2 was further investigated. ERalpha/HBD/V376R could bind to PNRC or PNRC2, with similar affinity as wild-type ERalpha/HBD, and the transactivation activity of ERalpha/V376R was enhanced 5-fold by PNRC. Since GRIP1, a well-characterized coactivator, was found not to be able to enhance the transactivation function of this mutant, our results indicate that the PNRC-ERalpha interaction interface is not exactly identical to that of GRIP1-ERalpha interaction.
Zhou
Dujin
D
Department of Surgical Research, Beckman Research Institute of City of Hope, 1450 East Duarte Road, Duarte, CA 91010, USA.
Ye
Jing Jing
JJ
Li
Yuping
Y
Lui
Ki
K
Chen
Shiuan
S
D020816:Amino Acid Motifs; D001665:Binding Sites; D047628:Estrogen Receptor alpha / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011392:Proline / Q000032:analysis; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000378:metabolism*; D015534:Trans-Activators / Q000737:chemistry* / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018909:src Homology Domains
D047628:Estrogen Receptor alpha; D009687:Nuclear Proteins; C096395:PNRC1 protein, human; C437718:PNRC2 protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D015534:Trans-Activators; D014157:Transcription Factors; D011392:Proline