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Publication Abstract from PubMed

Ca(2+) influx through high-voltage-activated calcium channels (HVACCs) controls diverse cellular functions. A critical feature enabling a singular signal, Ca(2+) influx, to mediate disparate functions is diversity of HVACC pore-forming alpha(1) and auxiliary Ca(V)beta(1)-Ca(V)beta(4) subunits. Selective Ca(V)alpha(1) blockers have enabled deciphering their unique physiological roles. By contrast, the capacity to post-translationally inhibit HVACCs based on Ca(V)beta isoform is non-existent. Conventional gene knockout/shRNA approaches do not adequately address this deficit owing to subunit reshuffling and partially overlapping functions of Ca(V)beta isoforms. Here, we identify a nanobody (nb.E8) that selectively binds Ca(V)beta(1) SH3 domain and inhibits Ca(V)beta(1)-associated HVACCs by reducing channel surface density, decreasing open probability, and speeding inactivation. Functionalizing nb.E8 with Nedd4L HECT domain yielded Chisel-1 which eliminated current through Ca(V)beta(1)-reconstituted Ca(V)1/Ca(V)2 and native Ca(V)1.1 channels in skeletal muscle, strongly suppressed depolarization-evoked Ca(2+) influx and excitation-transcription coupling in hippocampal neurons, but was inert against Ca(V)beta(2)-associated Ca(V)1.2 in cardiomyocytes. The results introduce an original method for probing distinctive functions of ion channel auxiliary subunit isoforms, reveal additional dimensions of Ca(V)beta(1) signaling in neurons, and describe a genetically-encoded HVACC inhibitor with unique properties.

Selective posttranslational inhibition of Ca(V)beta(1)-associated voltage-dependent calcium channels with a functionalized nanobody.,Morgenstern TJ, Nirwan N, Hernandez-Ochoa EO, Bibollet H, Choudhury P, Laloudakis YD, Ben Johny M, Bannister RA, Schneider MF, Minor DL Jr, Colecraft HM Nat Commun. 2022 Dec 9;13(1):7556. doi: 10.1038/s41467-022-35025-7. PMID:36494348^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.