The lipidated connexin mimetic peptide SRPTEKT-Hdc is a potent inhibitor of Cx43 channels with specificity for the pS368 phospho-isoform
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Final Accepted Manuscript
Author
Cotter, Maura LBoitano, Scott
Lampe, Paul D
Solan, Joell L
Vagner, Josef
Ek-Vitorin, Jose F
Burt, Janis M
Affiliation
Univ Arizona, Dept PharmacolUniv Arizona, Bio5 Inst
Univ Arizona, Asthma & Airway Dis Res Ctr
Univ Arizona, Dept Physiol
Issue Date
2019-10-07Keywords
Ca2+-wave propagationconformation-specific gap junction channel inhibitor
connexin 43
hemichannel inhibitor
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AMER PHYSIOLOGICAL SOCCitation
Cotter, Maura L., et al. "The lipidated connexin mimetic peptide SRPTEKT-Hdc is a potent inhibitor of Cx43 channels with specificity for the pS368 phospho-isoform." American Journal of Physiology-Cell Physiology 317.4 (2019): C825-C842.Rights
Copyright © 2019 the American Physiological Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Connexin (Cx) mimetic peptides derived from extracellular loop II sequences (e.g., Gap27: SRPTEKTIFII; Peptide5: VDCFLSRPTEKT) have been used as reversible, Cx-specific blockers of hemichannel (HCh) and gap junction channel (GJCh) function. These blockers typically require high concentrations (~5 µM, <1 h for HCh; ~100 µM, >1 h for GJCh) to achieve inhibition. We have shown that addition of a hexadecyl (Hdc) lipid tail to the conserved SRPTEKT peptide sequence (SRPTEKT-Hdc) results in a novel, highly efficacious, and potent inhibitor of mechanically induced Ca2+-wave propagation (IC50 64.8 pM) and HCh-mediated dye uptake (IC50 45.0 pM) in Madin-Darby canine kidney cells expressing rat Cx43 (MDCK43). The lack of similar effect on dye coupling (NBD-MTMA) suggested channel conformation-specific inhibition. Here we report that SRPTEKT-Hdc inhibition of Ca2+-wave propagation, dye coupling, and dye uptake depended on the functional configuration of Cx43 as determined by phosphorylation at serine 368 (S368). Ca2+-wave propagation was enhanced in MDCK cells expressing single-site mutants of Cx43 that mimicked (MDCK43-S368D) or favored (MDCK43-S365A) phosphorylation at S368. Furthermore, SRPTEKT-Hdc potently inhibited GJCh-mediated Ca2+-wave propagation (IC50 230.4 pM), dye coupling, and HCh-mediated dye uptake in MDCK43-S368D and -S365A cells. In contrast, Ca2+-wave propagation, dye coupling, and dye uptake were largely unaffected (IC50 12.3 μM) by SRPTEKT-Hdc in MDCK43-S368A and -S365D cells, mutations that mimic or favor dephosphorylation at S368. Together, these data indicate that SRPTEKT-Hdc is a potent inhibitor of physiological Ca2+-wave signaling mediated specifically by the pS368 phosphorylated form of Cx43.Note
12 month embargo; published online: 7 October 2019ISSN
0363-6143PubMed ID
31365296Version
Final accepted manuscriptSponsors
United States Department of Health & Human Services National Institutes of Health (NIH) - USA [HL-058732, HL-131712, HL-007249, NS-073664, GM-055632]ae974a485f413a2113503eed53cd6c53
10.1152/ajpcell.00160.2019
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