title: CML10, a variant of calmodulin, modulates ascorbic acid synthesis.
abstract: Calmodulins (CaMs) regulate numerous Ca(2+) -mediated cellular processes in plants by interacting with their respective downstream effectors. Due to the limited number of CaMs, other calcium sensors modulate the regulation of Ca(2+) -mediated cellular processes that are not managed by CaMs. Of 50 CaM-like (CML) proteins identified in Arabidopsis thaliana, we characterized the function of CML10. Yeast two-hybrid screening revealed phosphomannomutase (PMM) as a putative interaction partner of CML10. In vitro and in vivo interaction assays were performed to analyze the interaction mechanisms of CML10 and PMM. PMM activity and the phenotypes of cml10 knock-down mutants were studied to elucidate the role(s) of the CML10-PMM interaction. PMM interacted specifically with CML10 in the presence of Ca(2+) through its multiple interaction motifs. This interaction promoted the activity of PMM. The phenotypes of cml10 knock-down mutants were more sensitive to stress conditions than wild-type plants, corresponding with the fact that PMM is an enzyme which modulates the biosynthesis of ascorbic acid, an antioxidant. The results of this research demonstrate that a calcium sensor, CML10, which is an evolutionary variant of CaM, modulates the stress responses in Arabidopsis by regulating ascorbic acid production.
authors: Division of Life Sciences, Korea University, Seoul, 136-701, Korea.
authors: Kwang-Moon
authors: KM
authors: Cho
authors: Division of Life Sciences, Korea University, Seoul, 136-701, Korea.
authors: Ha Thi Kim
authors: HT
authors: Nguyen
authors: Division of Life Sciences, Korea University, Seoul, 136-701, Korea.
authors: Soo Youn
authors: SY
authors: Kim
authors: Division of Life Sciences, Korea University, Seoul, 136-701, Korea.
authors: Jin Seok
authors: JS
authors: Shin
authors: Graduate School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701, Korea.
authors: Dong Hwa
authors: DH
authors: Cho
authors: Division of Life Sciences, Korea University, Seoul, 136-701, Korea.
authors: Seung Beom
authors: SB
authors: Hong
authors: Division of Life Sciences, Korea University, Seoul, 136-701, Korea.
authors: Jeong Sheop
authors: JS
authors: Shin
authors: Food Science and Technology, Division of Engineering, Seoil University, Seoul, 131-702, Korea.
authors: Sung Han
authors: SH
authors: Ok
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001205:Ascorbic Acid / Q000096:biosynthesis* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D018384:Oxidative Stress / Q000502:physiology; D017875:Phosphotransferases (Phosphomutases) / Q000235:genetics / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; C542165:CaBP22 protein, Arabidopsis; D002147:Calmodulin; D017875:Phosphotransferases (Phosphomutases); C052799:phosphomannomutase; D001205:Ascorbic Acid; D002118:Calcium
keywords: Arabidopsis thaliana; abiotic stress; ascorbic acid (AsA); calcium signaling; calmodulin (CaM); calmodulin-like (CML); phosphomannomutase (PMM)