title: Identification of a novel peptide that interferes with the chemical regulation of connexin43.
abstract: The carboxyl-terminal domain of connexin43 (Cx43CT) is involved in various intra- and intermolecular interactions that regulate gap junctions. Here, we used phage display to identify novel peptidic sequences that bind Cx43CT and modify Cx43 regulation. We found that Cx43CT binds preferentially to peptides containing a sequence RXP, where X represents any amino acid and R and P correspond to the amino acids arginine and proline, respectively. A biased "RXP library" led to the identification of a peptide (dubbed "RXP-E") that bound Cx43CT with high affinity. Nuclear magnetic resonance data showed RXP-E-induced shifts in the resonance peaks of residues 343 to 346 and 376 to 379 of Cx43CT. Patch-clamp studies revealed that RXP-E partially prevented octanol-induced and acidification-induced uncoupling in Cx43-expressing cells. Moreover, RXP-E increased mean open time of Cx43 channels. The full effect of RXP-E was dependent on the integrity of the CT domain. These data suggest that RXP-based peptides could serve as tools to help determine the role of Cx43 as a regulator of function in conditions such as ischemia-induced arrhythmias.
authors.affiliation: Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA.
authors.forename: Junko
authors.initials: J
authors.lastname: Shibayama
authors.forename: Rebecca
authors.initials: R
authors.lastname: Lewandowski
authors.forename: Fabien
authors.initials: F
authors.lastname: Kieken
authors.forename: Wanda
authors.initials: W
authors.lastname: Coombs
authors.forename: Sejal
authors.initials: S
authors.lastname: Shah
authors.forename: Paul L
authors.initials: PL
authors.lastname: Sorgen
authors.forename: Steven M
authors.initials: SM
authors.lastname: Taffet
authors.forename: Mario
authors.initials: M
authors.lastname: Delmar
mesh_terms: D000143:Acids / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002450:Cell Communication / Q000187:drug effects; D045744:Cell Line, Tumor; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism*; D017629:Gap Junctions / Q000502:physiology; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D000442:Octanols / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010446:Peptide Fragments / Q000187:drug effects; D019151:Peptide Library; D010455:Peptides / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D000143:Acids; D002352:Carrier Proteins; D018031:Connexin 43; D007473:Ion Channels; D000442:Octanols; D010446:Peptide Fragments; D019151:Peptide Library; D010455:Peptides; C532149:RXP-E peptide; D014475:Uncoupling Agents