Regulation of Connexin-43-mediated Growth Inhibition by a Phosphorylatable Amino-acid is Independent of Gap Junction-forming Ability.
From: Department of Human Anatomy and Cell Sciences and Physiology, University of Manitoba, Winnipeg, R2H 2A6, Canada.
Molecular and cellular biochemistry
- Publish Date: Sep 2006
- ISSN: 0300-8177
- Volume: 289
- Issue: 1-2
- Pages: 201-7
- Medium: Print
- Language: English
- Citation (JAMA): Dang Xitong, Jeyaraman Madhumathy, Kardami Elissavet, et al. Regulation of Connexin-43-mediated Growth Inhibition by a Phosphorylatable Amino-acid is Independent of Gap Junction-forming Ability.. Mol. Cell. Biochem. Sep 2006;289:201-7
Abstract
The ability of the gap junction phosphoprotein connexin-43 (Cx43) to inhibit DNA synthesis in primary cardiomyocytes is regulated by serine (S) 262, a protein kinase C phosphorylation site that also affects metabolic coupling. We have now examined if the S262-regulated growth suppression is operating in transformed cells and if so whether it depends on gap junction channel forming ability. Serine 262 became phosphorylated in response to protein kinase C stimulation in HEK293 cells transiently expressing either Cx43 or the non-channel-forming carboxy-terminal tail of Cx43 (Cx43CT). Expression of either wild type Cx43 or Cx43CT inhibited DNA synthesis, as did their mutated versions simulating lack of phosphorylation by carrying an S262-to-alanine substitution. The ability to inhibit DNA synthesis was eliminated when expressing mutated versions of either Cx43 or Cx43CT simulating constitutive phosphorylation by carrying an S262-to-aspartate substitution. We conclude that S262 phosphorylation cancels growth inhibition by Cx43 independently of channel-forming ability.
Mesh Headings (Keywords): Cell Proliferation, Cells, Cultured, Connexin 43, DNA, Gap Junctions, Humans, Mutation, Phosphorylation, Phosphoserine
Check for Full Text / PubMed Unique Identifier (PMID): 16718370
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