Novel calcium-binding GTPase (AtCBG) involved in ABA-mediated salt stress signaling in Arabidopsis.
We have identified a novel Ca(2+)-signal sensing GTPase (643 amino acid residues with an estimated molecular mass of 79 kDa) from the Arabidopsis genome database. This protein contains a RHO-like GTPase domain at the N-terminus (15-184 amino acids) and two calcium-binding EF-hand motifs (199-227 and 319-347 amino acids, respectively). It has the capability to bind calcium and hydrolyze GTP; in addition, its GTPase activity is regulated by changes in Ca(2+) concentration. The expression of this gene was induced by ABA and salt stresses, and specific knock-out mutants were highly sensitive to ABA and salt treatments. These findings suggest that this protein is a novel ABA- and salt stress-related Ca(2+) signal transducer.
Jayasekaran
Kandakumar
K
School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Korea.
Kim
Kyung-Nam
KN
Vivekanandan
Munusamy
M
Shin
Jeong Sheop
JS
Ok
Sung Han
SH
D000040:Abscisic Acid / Q000494:pharmacology*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D010937:Plant Growth Regulators / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D015398:Signal Transduction; D012965:Sodium Chloride / Q000494:pharmacology*
D029681:Arabidopsis Proteins; D008840:Microfilament Proteins; D010937:Plant Growth Regulators; D011994:Recombinant Proteins; C560263:VLN4 protein, Arabidopsis; D012965:Sodium Chloride; D000040:Abscisic Acid; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D002118:Calcium