Heteromeric gap junction channels in rat hepatocytes in which the expression of connexin26 is induced

Mol Cells. 1998 Jun 30;8(3):295-300.

Abstract

More than one isotype of the gap junction channel-forming protein subunit, known as connexin, are synthesized in most mammalian cells. Using a modified primary cell culture of rat hepatocytes, in which both connexin32 and connexin26 were expressed in a comparable degree, the molecular composition of connexin subtypes in a gap junction channel (i.e., homomeric or heteromeric) was studied. A fluorescent dye Lucifer Yellow-coupling among hepatocytes was blocked in the presence of 20 microM beta-glycyrrhetinic acid, and antagonist for the gap junction channel. Similarly, either one of the antibodies raised against connexin32 or connexin26 completely inhibited dye-coupling activity among hepatocytes. In addition, we studied the dye-coupling properties at different extracellular pHs in two primary rat hepatocytes: one in which connexin26 was induced, and the other which expresses connexin32 as a major gap junction channel protein. The dye-coupling among the connexin26-induced hepatocytes was more sensitive to lowering pHs than among the normal hepatocytes, in which less than 5% of gap junction protein is connexin26. Taken together, data obtained in our study strongly suggest that the connexins (32 & 26) are assembled to form heteromeric, rather than homomeric, gap junction channels in the connexin226-induced rat hepatocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Topical
  • Animals
  • Anti-Inflammatory Agents / pharmacology
  • Antibodies / pharmacology
  • Connexin 26
  • Connexins / chemistry*
  • Connexins / genetics
  • Connexins / immunology
  • Dimerization
  • Fluorescent Dyes
  • Gap Junctions / chemistry*
  • Gap Junctions / drug effects
  • Gap Junctions / metabolism
  • Gene Expression / genetics
  • Gene Expression Regulation
  • Glycyrrhetinic Acid / pharmacology
  • Hydrogen-Ion Concentration
  • Isoquinolines
  • Liver / chemistry
  • Liver / cytology*
  • Liver / metabolism*
  • Male
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Anti-Inflammatory Agents
  • Antibodies
  • Connexins
  • Fluorescent Dyes
  • Isoquinolines
  • connexin 32
  • Connexin 26
  • lucifer yellow
  • Glycyrrhetinic Acid