The subcellular localization of an unusual rice calmodulin isoform, OsCaM61, depends on its prenylation status.
Calmodulin (CaM) is a small Ca2+-binding protein highly conserved in eukaryotes. We have reported previously a novel rice CaM-like protein (OsCaM61) which contains an N-terminal CaM domain and a C-terminal extension with a potential prenylation site. Here we report in vitro activity assays confirm OsCaM61 as a functional CaM. Using the green fluorescent protein (GFP) as a visual marker, we further studied the subcellular localization of OsCaM61 in stably transformed tobacco cells. The GFP-OsCaM61 fusion protein was membrane-associated whereas OsCaM61-GFP was mainly detected in the nucleoplasm. GFP-OsCaM61 was transported into the nucleoplasm upon a block in isoprenoid biosynthesis by mevinolin treatment of cells. These results indicate that the prenylated OsCaM61 molecules are mainly membrane-associated whereas its unprenylated counterparts are transported into the nucleoplasm. Thus, OsCaM61 may play functions in co-ordinating Ca2+ signaling with isoprenoid metabolism.
Dong
Aiwu
A
Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China. awdong1970@yahoo.com
Xin
Hua
H
Yu
Yu
Y
Sun
Chongrong
C
Cao
Kaiming
K
Shen
Wen-Hui
WH
D000595:Amino Acid Sequence; D001692:Biological Transport / Q000187:drug effects; D002147:Calmodulin / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D017124:Conserved Sequence; D003593:Cytoplasm / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D008148:Lovastatin / Q000494:pharmacology; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017368:Protein Prenylation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D002147:Calmodulin; D008164:Luminescent Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D003907:Dexamethasone; D008148:Lovastatin; D010727:Phosphoric Diester Hydrolases