5k8q
From Proteopedia
Crystal Structure of Calcium-loaded Calmodulin in complex with STRA6 CaMBP2-site peptide.
Structural highlights
DiseaseCALM1_HUMAN The disease is caused by mutations affecting the gene represented in this entry. Mutations in CALM1 are the cause of CPVT4. The disease is caused by mutations affecting the gene represented in this entry. Mutations in CALM1 are the cause of LQT14. FunctionCALM1_HUMAN Calmodulin mediates the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding. Among the enzymes to be stimulated by the calmodulin-calcium complex are a number of protein kinases and phosphatases. Together with CCP110 and centrin, is involved in a genetic pathway that regulates the centrosome cycle and progression through cytokinesis (PubMed:16760425). Mediates calcium-dependent inactivation of CACNA1C (PubMed:26969752). Positively regulates calcium-activated potassium channel activity of KCNN2 (PubMed:27165696).[1] [2] [3] [4] Publication Abstract from PubMedVitamin 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. Structure of the STRA6 receptor for retinol uptake.,Chen Y, Clarke OB, Kim J, Stowe S, Kim YK, Assur Z, Cavalier M, Godoy-Ruiz R, von Alpen DC, Manzini C, Blaner WS, Frank J, Quadro L, Weber DJ, Shapiro L, Hendrickson WA, Mancia F Science. 2016 Aug 26;353(6302). pii: aad8266. doi: 10.1126/science.aad8266. PMID:27563101[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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