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Structure of the STRA6 receptor for retinol uptake.

ABSTRACT: Vitamin A homeostasis is critical to normal cellular function. Retinol-binding protein (RBP) is the sole specific carrier in the bloodstream for hydrophobic retinol, the main form in which vitamin A is transported. The integral membrane receptor STRA6 mediates cellular uptake of vitamin A by recognizing RBP-retinol to trigger release and internalization of retinol. We present the structure of zebrafish STRA6 determined to 3.9-angstrom resolution by single-particle cryo-electron microscopy. STRA6 has one intramembrane and nine transmembrane helices in an intricate dimeric assembly. Unexpectedly, calmodulin is bound tightly to STRA6 in a noncanonical arrangement. Residues involved with RBP binding map to an archlike structure that covers a deep lipophilic cleft. This cleft is open to the membrane, suggesting a possible mode for internalization of retinol through direct diffusion into the lipid bilayer.

SUBMITTER: Chen Y

PROVIDER: S-EPMC5114850 | biostudies-literature |

REPOSITORIES: biostudies-literature

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The retinol-binding protein receptor STRA6 regulates diurnal insulin responses.

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Project description:This SuperSeries is composed of the SubSeries listed below.

2023-09-06 | GSE242149 | GEO

The retinol-binding protein receptor STRA6 contributes to the pathogenesis of adenomyosis via Wnt/β-catenin pathway depression [RNA]

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2023-09-06 | GSE242145 | GEO

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