11 Novel calcium-binding GTPase (AtCBG) involved in ABA-mediated salt stress signaling in Arabidopsis. Kim Kyung-Nam Ok Sung Han Shin Jeong Sheop 2006 Nov Vivekanandan Munusamy 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. 25 Jayasekaran Kandakumar et al. 2006 Nov. Plant Cell Rep. 25(11):1255-62. 16832621 1255-62 Jayasekaran Kandakumar