Centrin is essential for the activity of the ciliary reversal-coupled voltage-gated Ca2+ channels.
Voltage-gated Ca(2+) channels play a critical role in controlling Ca(2+) entry in various cells. Ciliary reversal in Paramecium depends on the Ca(2+) influx through voltage-gated Ca(2+) channels on the ciliary membrane. One of the voltage-gated Ca(2+) channel mutants in Paramecium caudatum, cnrC, neither produces Ca(2+) action potentials nor responds to any depolarizing stimuli. Here, we report that the cnrC(+) gene product is P. caudatum centrin (Pccentrin1p), a member of the Ca(2+)-binding EF-hand protein superfamily. The Pccentrin1p gene of cnrC was found to contain a single-base deletion, a mutation that caused the loss of the fourth EF-hand of Pccentrin1p. Moreover, the wild-type Ca(2+) channel function was impaired by Pccentrin1p gene silencing, leading to the loss of current-evoked Ca(2+) action potentials and stimulated ciliary reversal. These results demonstrate that Pccentrin1p is indispensable for the activity of the voltage-gated Ca(2+) channels that control ciliary reversal in Paramecium.
Gonda
Kohsuke
K
Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
Yoshida
Akiko
A
Oami
Kazunori
K
Takahashi
Mihoko
M
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D002923:Cilia / Q000502:physiology*; D020868:Gene Silencing / Q000502:physiology; D015640:Ion Channel Gating / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D010247:Paramecium / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism
D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D002868:Chromosomal Proteins, Non-Histone; D011994:Recombinant Proteins; C056608:caltractin; D002118:Calcium