6os4
Calmodulin in complex with farnesyl cysteine methyl esterCalmodulin in complex with farnesyl cysteine methyl ester
Structural highlights
Disease[CALM1_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. Function[CALM1_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 PubMedKRAS4b is a small guanosine triphosphatase (GTPase) protein that regulates several signal transduction pathways that underlie cell proliferation, differentiation, and survival. KRAS4b function requires prenylation of its C terminus and recruitment to the plasma membrane, where KRAS4b activates effector proteins including the RAF family of kinases. The Ca(2+)-sensing protein calmodulin (CaM) has been suggested to regulate the localization of KRAS4b through direct, Ca(2+)-dependent interaction, but how CaM and KRAS4b functionally interact is controversial. Here, we determined a crystal structure, which was supported by solution nuclear magnetic resonance (NMR), that revealed the sequestration of the prenyl moiety of KRAS4b in the hydrophobic pocket of the C-terminal lobe of Ca(2+)-bound CaM. Our engineered fluorescence resonance energy transfer (FRET)-based biosensor probes (CaMeRAS) showed that, upon stimulation of Ca(2+) influx by extracellular ligands, KRAS4b reversibly translocated in a Ca(2+)-CaM-dependent manner from the plasma membrane to the cytoplasm in live HeLa and HEK293 cells. These results reveal a mechanism underlying the inhibition of KRAS4b activity by Ca(2+) signaling pathways. Calmodulin disrupts plasma membrane localization of farnesylated KRAS4b by sequestering its lipid moiety.,Grant BMM, Enomoto M, Back SI, Lee KY, Gebregiworgis T, Ishiyama N, Ikura M, Marshall CB Sci Signal. 2020 Mar 31;13(625). pii: 13/625/eaaz0344. doi:, 10.1126/scisignal.aaz0344. PMID:32234958[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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