Functional analysis of a rice putative voltage-dependent Ca2+ channel, OsTPC1, expressed in yeast cells lacking its homologous gene CCH1.
We isolated a cDNA (OsTPC1) from rice that was homologous to AtTPC1, a putative voltage-dependent Ca(2+) channel (VDCC) gene of Arabidopsis thaliana. The hydropathy profile of its deduced amino acid sequence showed significant structural features of the alpha 1-subunit of animal VDCCs. Functional analysis using a heterologous yeast expression system showed that OsTPC1 facilitates Ca(2+) permeation. The K(m) value for Ca(2+) of OsTPC1, 47.5 micro M, was comparable to that of intrinsic CCH1, a candidate VDCC in yeast. Ca(2+) permeation by OsTPC1 was inhibited by verapamil, a VDCC blocker. These findings indicate for the first time that OsTPC1 is a putative VDCC in rice.
Hashimoto
Kenji
K
Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo, 184-8588 Japan.
Saito
Mikako
M
Matsuoka
Hideaki
H
Iida
Kazuko
K
Iida
Hidetoshi
H
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D003470:Culture Media; D015870:Gene Expression; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015003:Yeasts / Q000166:cytology / Q000235:genetics
C108765:CCH1 protein, S cerevisiae; D015220:Calcium Channels; D003470:Culture Media; D010940:Plant Proteins; D029701:Saccharomyces cerevisiae Proteins; D002118:Calcium