PUBLICATION

Impaired Cx43 gap junction endocytosis causes morphological and functional defects in zebrafish

Authors
Hyland, C., Mfarej, M., Hiotis, G., Lancaster, S., Novak, N., Iovine, M.K., Falk, M.M.
ID
ZDB-PUB-210812-7
Date
2021
Source
Molecular biology of the cell   32(20): ar13 (Journal)
Registered Authors
Iovine, M. Kathryn
Keywords
none
MeSH Terms
  • Animals
  • Cell Communication
  • Cell Line
  • Cells, Cultured
  • Connexins/metabolism
  • Endocytosis/physiology
  • Gap Junctions/metabolism
  • Membrane Proteins/genetics
  • Membrane Proteins/metabolism*
  • Phosphorylation
  • Protein Domains
  • Protein Transport
  • Zebrafish
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed
34379446 Full text @ Mol. Biol. Cell
Abstract
Gap junctions mediate direct cell-to-cell communication by forming channels that physically couple cells, thereby linking their cytoplasm, permitting the exchange of molecules, ions, and electrical impulses. Gap junctions are assembled from connexin (Cx) proteins, with connexin 43 (Cx43) being the most ubiquitously expressed and best studied. While the molecular events that dictate the Cx43 life cycle have largely been characterized, the unusually short half-life of connexins of only 1-5 hours, resulting in constant endocytosis and biosynthetic replacement of gap junction channels has remained puzzling. The Cx43 C-terminal (CT) domain serves as the regulatory hub of the protein affecting all aspects of gap junction function. Here, deletion within the Cx43 CT (amino acids 256-289), a region known to encode key residues regulating gap junction turnover is employed to examine the effects of dysregulated Cx43 gap junction endocytosis using cultured cells (Cx43∆256-289) and a zebrafish model (cx43lh10). We report that this CT deletion causes defective gap junction endocytosis as well as increased gap junction intercellular communication (GJIC). Increased Cx43 protein content in cx43lh10 zebrafish, specifically in the cardiac tissue, larger gap junction plaques and longer Cx43 protein half-lives coincide with severely impaired development. Our findings demonstrate for the first time that Cx43 gap junction endocytosis is an essential aspect of gap junction function and when impaired, gives rise to significant physiological problems as revealed here for cardiovascular development and function. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].
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