(full paper is archived in the Miller Library)
Title: Hypobranchial gland secretion from Calliostoma canaliculatum slows activation of voltage-gated potassium channels
Student Author(s): Lu, Natalie
Faculty Advisor(s): Gilly, William
Location: Final Papers Biology 175H
Date: June 1998
Abstract: The marine prosobranch gastropod Calliostoma canaliculatum secretes a noxious substance, Yellow Stuff (YS), as a mechanism of chemical defense against predatory sea stars. The effects of YS from the homogenized hypobranchial gland on voltage-gated K+ channels were characterized with voltage clamp techniques for multiple subfamilies of cloned K+ channels expressed in three different cell systems (insect Sf9 cells, mammalian HEK 293 cells, and Xenopus oocytes). The most profound effect was slowed activation kinetics with very little change to deactivation kinetics. Other effects included a decrease in peak conductance and a shift in the voltage-dependence of peak conductance to more positive potentials. YS secretion collected from electrical stimulation of the hypobranchial gland gave the same effects. Fractionation of YS produced one active fraction that produced effects similar to that of the unfractionated YS. Elucidating the mechanism by which YS mediates its effects and further establishing its selectivity for different K+ channel isoforms will provide a useful tool for further studying voltage-gated K+ channels.