TY - JOUR
T1 - Evidence for the presence of a free C-Terminal fragment of Cx43 in cultured cells
AU - Joshi-Mukherjee, Rosy
AU - Coombs, Wanda
AU - Burrer, Christine
AU - Alvarez de Mora, Isabel
AU - Delmar, Mario
AU - Taffet, Steven M.
N1 - Funding Information:
Received 20 November 2006; accepted 16 February 2007. This work was supported by NIH grants GM57691, HL080602 and HL39707. Address correspondence to Dr Steven Taffet, SUNY Upstate Medical University, Department of Microbiology, 750 E. Adams St, Syracuse, NY 13210. E-mail taffets@upstate.edu. Phone: (315) 464-5419. Fax (315) 464-7668.
PY - 2007/3
Y1 - 2007/3
N2 - 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.
AB - 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.
KW - Connexin
KW - Connexin 43
KW - Cx43
KW - Cx43 C-terminal fragment
KW - Gap junction
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U2 - 10.1080/15419060701402320
DO - 10.1080/15419060701402320
M3 - Article
C2 - 17668351
AN - SCOPUS:34547653650
SN - 1541-9061
VL - 14
SP - 75
EP - 84
JO - Cell Adhesion and Communication
JF - Cell Adhesion and Communication
IS - 2-3
ER -