Centrin controls the activity of the ciliary reversal-coupled voltage-gated Ca channels Ca-dependently
نویسندگان
چکیده
In Paramecium, ciliary reversal is coupled with voltage-gated Ca 2+ channels on the ciliary membrane. We previously isolated a P. caudatum mutant, cnrC, with a malfunction of the Ca 2+ channels and discovered that the channel activity of cnrC was restored by transfection of the P. caudatum centrin (Pccentrin1p) gene, which encodes a member of the Ca 2+-binding EF-hand protein family. In this study, we injected various mutated Pccentrin1p genes into cnrC and investigated whether these genes restore the Ca 2+ channel activity of cnrC. A Pccentrin1p mutant gene lacking Ca 2+ sensitivity of the third and fourth EF-hands lost the ability to restore the channel function of cnrC, and mutation of the fourth EF-hand caused more serious impairment than mutation of the third EF-hand. Moreover, a Pccentrin1p gene lacking the N-terminal 34-amino acid sequence also lost the ability to restore the channel activity. Native-PAGE analysis demonstrated that the N-terminal sequence is important for the Ca 2+-dependent structural change of Pccentrin1p. These results demonstrate that Pccentrin1p Ca 2+-dependently regulates the Ca 2+ channel activity in vivo.
منابع مشابه
Centrin controls the activity of the ciliary reversal-coupled voltage-gated Ca2+ channels Ca2+-dependently.
In Paramecium, ciliary reversal is coupled with voltage-gated Ca(2+) channels on the ciliary membrane. We previously isolated a P. caudatum mutant, cnrC, with a malfunction of the Ca(2+) channels and discovered that the channel activity of cnrC was restored by transfection of the P. caudatum centrin (Pccentrin1p) gene, which encodes a member of the Ca(2+)-binding EF-hand protein family. In this...
متن کاملCloning, localization, and axonemal function of Tetrahymena centrin.
Centrin, an EF hand Ca(2+) binding protein, has been cloned in Tetrahymena thermophila. It is a 167 amino acid protein of 19.4 kDa with a unique N-terminal region, coded by a single gene containing an 85-base pair intron. It has > 80% homology to other centrins and high homology to Tetrahymena EF hand proteins calmodulin, TCBP23, and TCBP25. Specific cellular localizations of the closely relate...
متن کاملFunctional dependence of Ca(2+)-activated K+ current on L- and N-type Ca2+ channels: differences between chicken sympathetic and parasympathetic neurons suggest different regulatory mechanisms.
The influx of Ca2+ ions controls many important processes in excitable cells, including the regulation of the gating of Ca(2+)-activated K+ channels (the current IK[Ca]). Various IK[Ca] channels contribute to the regulation of the action-potential waveform, the repetitive discharge of spikes, and the secretion of neurotransmitters. It is thought that large-conductance IK[Ca] channels must be cl...
متن کاملVisualization of calcium transients controlling orientation of ciliary beat
To image changes in intraciliary Ca controlling ciliary motility, we microinjected Ca Green dextran, a visible wavelength fluorescent Ca indicator, into eggs or two cell stages of the ctenophore Mnemiopsis leidyi. The embryos developed normally into free-swimming, approximately 0.5 mm cydippid larvae with cells and ciliary comb plates (approximately 100 microns long) loaded with the dye. Comb p...
متن کاملG-proteins modulate cumulative inactivation of N-type (Cav2.2) calcium channels.
Precise regulation of N-type (Ca(V)2.2) voltage-gated calcium channels (Ca-channels) controls many cellular functions including neurotransmitter and hormone release. One important mechanism that inhibits Ca2+ entry involves binding of G-protein betagamma subunits (Gbetagamma) to the Ca-channels. This shifts the Ca-channels from "willing" to "reluctant" gating states and slows activation. Voltag...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2007