AJP - Regulatory, Integrative and Comparative Physiology, Vol 262, Issue 3 542-R545, Copyright © 1992 by American Physiological Society
Inhibition of Ca2+ and K+ currents by "antifreeze" proteins
B. Rubinsky, M. Mattioli, A. Arav, B. Barboni and G. L. Fletcher
Department of Mechanical Engineering, University of California, Berkeley 94720.
For the last two decades, the research on fish "antifreeze" proteins has
focused exclusively on their ability to depress noncolligatively blood
plasma freezing points, presumably by binding to ice crystals. We report
evidence that antifreeze polypeptides from the winter flounder
(Pseudopleuronectes americanus) have another special property, the ability
to block ion channels. In experiments with porcine granulosa cells we show,
using the patch-clamp technique in the whole cell configuration, that these
proteins suppress effectively calcium and potassium currents. The results
of dose-response studies indicate a protein-protein interaction mechanism.
