6pbx | pdb_00006pbx
Single particle cryo-EM structure of the voltage-gated K+ channel Eag1 3-13 deletion mutant bound to calmodulin (conformation 2)
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[KCNH1_RAT] Pore-forming (alpha) subunit of a voltage-gated delayed rectifier potassium channel. Channel properties may be modulated by subunit assembly, but not by cyclic nucleotides (By similarity). Mediates IK(NI) current in myoblasts (By similarity). Involved in the regulation of cell proliferation and differentiation, as adipogenic and osteogenic differentiation in bone marrow-derived mesenchymal stem cells (MSCs) (By similarity).[UniProtKB:O95259][UniProtKB:Q60603] [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 PubMedVoltage-gated potassium channels (Kvs) are gated by transmembrane voltage sensors (VS) that move in response to changes in membrane voltage. Kv10.1 or Eag1 also has three intracellular domains: PAS, C-linker, and CNBHD. We demonstrate that the Eag1 intracellular domains are not required for voltage-dependent gating but likely interact with the VS to modulate gating. We identified specific interactions between the PAS, CNBHD, and VS that modulate voltage-dependent gating and provide evidence that VS movement destabilizes these interactions to promote channel opening. Additionally, mutation of these interactions renders Eag1 insensitive to calmodulin inhibition. The structure of the calmodulin insensitive mutant in a pre-open conformation suggests that channel opening may occur through a rotation of the intracellular domains and calmodulin may prevent this rotation by stabilizing interactions between the VS and intracellular domains. Intracellular domains likely play a similar modulatory role in voltage-dependent gating of the related Kv11-12 channels. Regulation of Eag1 gating by its intracellular domains.,Whicher JR, MacKinnon R Elife. 2019 Sep 6;8. pii: 49188. doi: 10.7554/eLife.49188. PMID:31490124[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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