Tissue-Specific Distribution of Differentially Phosphorylated Forms of Cx43

R. Kadle, J. T. Zhang, B. J. Nicholson

Research output: Contribution to journalArticlepeer-review

109 Scopus citations


Variants of the Cx43 gap junction protein have been detected on Western immunoblots by using an antipeptide antibody to the N-terminus of the protein. In heart ventricle, atrium, brain, retina, and uterus, different yet characteristic ratios of a broad 43-kDa band and a 39- to 40-kDa doublet were observed. These proteins (in lens epithelium, testes, and spleen) or their messages (in stomach, duodenum, kidney, and lung) were also detected in several nonexcitable systems but at consistently lower levels than found in electrically excitable tissues. The reproducible heterogeneity in electrophoretic mobility of Cx43 seen in different tissues does not appear to be due to proteolysis, since both the 43-kDa band and the 39- to 40-kDa doublet were recognized by an N-terminal as well as a C-terminal antibody. Furthermore, Northern (RNA) blots from different tissues show that both polypeptide profiles arise from indistinguishable transcripts. The conversion by alkaline phosphatase treatment of a predominantly 43-kDa profile (in heart) to a 39- to 40-kDa profile (characteristic of brain and protein translated in vitro from the RNA) suggests that the observed electrophoretic heterogeneity arises from tissue-wide differences in the phosphorylation state of Cx43.

Original languageEnglish (US)
Pages (from-to)363-369
Number of pages7
JournalMolecular and cellular biology
Issue number1
StatePublished - Jan 1991
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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