Structural analysis of estrogen receptors: interaction between estrogen receptors and cav-1 within the caveolae. Issue 2 (23rd August 2018)

• Record Type: Journal Article
• Authors: Pastore, Mayra B; Landeros, Rosalina Villalon; Chen, Dong-bao; Magness, Ronald R
• Is Part Of: Biology of reproduction. Volume 100:Issue 2(2019)
• Page Start: 495
• Page End: 504
• Publication Date: 2018-08-23
• Subjects: estrogen receptors -- ESR1 -- ESR2 -- ER-α, ER-β -- Caveolae -- pregnancy -- nitric oxide -- eNOS -- uterine vasculature -- endothelium; Reproduction -- Periodicals; Biology; Reproduction; Reproduction; Electronic journals; Periodicals; Periodicals; 571.805
• DOI: 10.1093/biolre/ioy188
• Languages: English
• ISSNs: 0006-3363

Abstract

Abstract: Pregnancy is a physiologic state of substantially elevated estrogen biosynthesis that maintains vasodilator production by uterine artery endothelial cells (P-UAECs) and thus uterine perfusion. Estrogen receptors (ER-α and ER-β; ESR1 and ESR2) stimulate nongenomic rapid vasodilatory responses partly through activation of endothelial nitric oxide synthase (eNOS). Rapid estrogenic responses are initiated by the ∼4% ESRs localized to the plasmalemma of endothelial cells. Caveolin-1 (Cav-1) interactions within the caveolae are theorized to influence estrogenic effects mediated by both ESRs. Hypothesis: Both ESR1 and ESR2 display similar spatial partitioning between the plasmalemma and nucleus of UAECs and have similar interactions with Cav-1 at the plasmalemma. Using transmission electron microscopy, we observed numerous caveolae structures in UAECs, while immunogold labeling and subcellular fractionations identified ESR1 and ESR2 in three subcellular locations: membrane, cytosol, and nucleus. Bioinformatics approaches to analyze ESR1 and ESR2 transmembrane domains identified no regions that facilitate ESR interaction with plasmalemma. However, sucrose density centrifugation and Cav-1 immunoisolation columns uniquely demonstrated very high protein–protein association only between ESR1, but not ESR2, with Cav-1. These data demonstrate (1) both ESRs localize to the plasmalemma, cytosol and nucleus; (2) neither ESR1 nor ESR2 contain a classic region that crosses the plasmalemma to facilitate attachment; and (3) ESR1, but not ESR2, can be detected in the caveolar subcellular domain demonstrating ESR1 is the only ESR bound in close proximity to Cav-1 and eNOS within this microdomain. Lack of protein–protein interaction between Cav-1 and ESR2 demonstrates a novel independent association of these proteins at the plasmalemma. Abstract : Since ESR1 and ESR2 plasma membrane location are respectively affiliated with Cav-1-dependent and Cav-1-indepenent mechanisms, a novel difference of ER regulation in endothelial cells derived from the uterine vasculature was identified.