Evidence for the presence of a free C-Terminal fragment of Cx43 in cultured cells

Rosy Joshi-Mukherjee, Wanda Coombs, Christine Burrer, Isabel Alvarez de Mora, Mario Delmar, Steven M. Taffet

Research output: Contribution to journalArticle

Abstract

Migration of the gap junction protein connexin 43 (Cx43) in SDS-PAGE yields 2 to 4 distinct bands, detectable in the 40-47 kDa range. Here, we show that antibodies against the carboxy-terminal domain of Cx43 recognized an additional 20-kDa product. This protein was detected in some culture cell lysates. The presence of the 20-kDa band was not prevented by the use of protease inhibitors (Complete® and phenylmethylsulfonyl fluoride (PMSF), 1-5 mM). The band was absent from cells treated with Cx43-specific RNAi, and from those derived from Cx43-deficient mice, indicating that this Cx43-immunoreactive protein is a product of the Cx43 gene. Treatment of CHO cells with cyclosporin A caused a reduction in the amount of full-length Cx43 and a concomitant increase in the amount of the 20-kDa band. Overall, our data show that a fraction of the Cx43-immunoreactive protein pool within a given cell may correspond to a C-terminal fragment of the protein.

Original languageEnglish (US)
Pages (from-to)75-84
Number of pages10
JournalCell Communication and Adhesion
Volume14
Issue number2-3
DOIs
StatePublished - Mar 1 2007
Externally publishedYes

Keywords

  • Connexin
  • Connexin 43
  • Cx43
  • Cx43 C-terminal fragment
  • Gap junction

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology

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