Is calmodulin involved in the regulation of gap junction permeability?
- 56 Downloads
The cell-to-cell channels of gap junctions mediate the direct exchange of ions and small metabolites between neighboring cells. A number of studies have shown that these channels close when the intracellular free calcium or hydrogen concentration increases, the result being cell-to-cell uncoupling. Since most of the calcium-activated biological phenomena are mediated by calmodulin (CaM), an obvious question is whether or not CaM is involved in the mechanism of cell coupling regulation. Data from the present study, showing the inhibitory effects of a calmodulin blocker on electrical uncoupling in Xenopus embryo cells, suggest a possible CaM participation in the uncoupling mechanism.
Key wordsGap junctions calmodulin trifluoperazine Xenopus embryo cell coupling
Unable to display preview. Download preview PDF.
- Blackmore, W.G., El-Rafai, J.-P., Dehaye, W.G., Strickland, B.P., Hughes, B.P., Eaton, J.H. (1981) Blockade of hepatic α-adrenergic receptors and responses by chlorpromazine and trifluoperazine. FEBS Lett.123:245–248.Google Scholar
- Cheung W.Y. (1980) Calmodulin plays a pivotal role in cellular regulation. Science207:19–27.Google Scholar
- Hertzberg, E.L., Gilula N.B. (1981) Liver gap junctions and lens fiber junctions: comparative analysis and calmodulin interactions. Cold Spring Harbor Symp. Quant. Biol.46:639–645.Google Scholar
- Kretsinger, R.H. (1980) Crystallographic studies of calmodulin and homologs. Ann. N.Y. Acad. Sci. 356:14–19.Google Scholar
- Lehrer, S.S., Leavis, P.C. (1974) Fluorescence and conformational changes caused by proton binding to troponin C. Biochem. Biophys. Res. Comm.58:159–165.Google Scholar
- Peracchia, C. (1980) Structural correlates of gap junction permeation. Int. Rev. Cytol.66:81–146.Google Scholar
- Peracchia, C. (1982) Calmodulin and gap junctions: reversible inhibition of electrical uncoupling by calmidazolium. J. Cell Biol.95:102a.Google Scholar
- Peracchia, C., Bernardini, G., Peracchia, L.L. (1981) A calmodulin inhibitor prevents gap junction crystallization and electrical uncoupling. J. Cell Biol.91:124a.Google Scholar
- Rose, B., Loewenstein, W.R. (1975) Permeability of cell junction depends on local cytoplasmic calcium activity. Nature (London),254:250–252.Google Scholar
- Rose, B., Rick. (1978) Intracellular pH, intracellular free Ca++, and junctional cell-cell coupling. J. Membr. Biol.44:377–415.Google Scholar
- Socolar, S.J., (1977) Appendix: the coupling coefficient as an index of junctional conductance. J. Membr. Biol.34:29–37.Google Scholar
- Spray, D.C., Harris, A.L., Bennett, M.V.L. (1981) Gap junctional conductance is simple and sensitive function of intracellular pH. Science211:712–715.Google Scholar
- Spray, D.C., Stern, J.H., Harris, A.L., Bennett, M.V.L. (1982) Gap junctional conductance: comparison of sensitivities to H and Ca ions. Proc. Natl. Acad. Sci. U.S.A.79:441–445.Google Scholar
- Turin, L., Warner, A.E. (1977) Carbon dioxide reversibly abolishes ionic communication between cells of early amphibian embryo. Nature (London)270:56–57.Google Scholar
- Turin, L., Warner, A.E. (1980) Intracellular pH in early Xenopus embryos: its effect on current flow between blastomeres. J. Physiol. (London)300:489–504.Google Scholar
- Van Belle, H. (1981) R 24571: a potent inhibitor of calmodulin-activated enzymes. Cell Calcium2:483–494.Google Scholar
- Weiss, B., Fertel, R., Figlin, R., Uzonov, P. (1974). Selective alteration of the activity of the multiple forms of adenosine 3′, 5′-monophosphate phosphodiesterase of rat cerebrum. Mol. Pharmacol.10:615–625.Google Scholar
- Welsh, M.J., Aster, J., Ireland, M., Alcala, J., Maisel, H. (1981) Calmodulin and gap junctions: localization of calmodulin and calmodulin binding sites in chick lens cells. J. Cell. Biol.91:123a.Google Scholar
- Welsh, M.J., Aster, J.C., Ireland, M., Alcala, J., Maisel, H. (1982) Calmodulin binds to chick lens gap junction protein in a calcium-independent manner. Science.216:642–644.Google Scholar