7wlj | pdb_00007wlj
CryoEM structure of human low-voltage activated T-type calcium channel Cav3.3 in complex with mibefradil (MIB)
Structural highlights
Function[CAC1I_HUMAN] Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. This channel gives rise to T-type calcium currents. T-type calcium channels belong to the 'low-voltage activated (LVA)' group and are strongly blocked by nickel and mibefradil. A particularity of this type of channels is an opening at quite negative potentials, and a voltage-dependent inactivation. T-type channels serve pacemaking functions in both central neurons and cardiac nodal cells and support calcium signaling in secretory cells and vascular smooth muscle. They may also be involved in the modulation of firing patterns of neurons which is important for information processing as well as in cell growth processes. Gates in voltage ranges similar to, but higher than alpha 1G or alpha 1H (By similarity). Publication Abstract from PubMedThe low-voltage activated T-type calcium channels regulate cellular excitability and oscillatory behavior of resting membrane potential which trigger many physiological events and have been implicated with many diseases. Here, we determine structures of the human T-type CaV3.3 channel, in the absence and presence of antihypertensive drug mibefradil, antispasmodic drug otilonium bromide and antipsychotic drug pimozide. CaV3.3 contains a long bended S6 helix from domain III, with a positive charged region protruding into the cytosol, which is critical for T-type CaV channel activation at low voltage. The drug-bound structures clearly illustrate how these structurally different compounds bind to the same central cavity inside the CaV3.3 channel, but are mediated by significantly distinct interactions between drugs and their surrounding residues. Phospholipid molecules penetrate into the central cavity in various extent to shape the binding pocket and play important roles in stabilizing the inhibitor. These structures elucidate mechanisms of channel gating, drug recognition, and actions, thus pointing the way to developing potent and subtype-specific drug for therapeutic treatments of related disorders. Structure, gating, and pharmacology of human CaV3.3 channel.,He L, Yu Z, Geng Z, Huang Z, Zhang C, Dong Y, Gao Y, Wang Y, Chen Q, Sun L, Ma X, Huang B, Wang X, Zhao Y Nat Commun. 2022 Apr 19;13(1):2084. doi: 10.1038/s41467-022-29728-0. PMID:35440630[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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