title: Calcineurin B-like 3 calcium sensor associates with and inhibits 5'-methylthioadenosine nucleosidase 2 in Arabidopsis.
abstract: Calcineurin B-like (CBL) proteins constitute a unique family of calcium sensor relays in plants. It is well known that CBLs detect the calcium signals elicited by a variety of abiotic stresses and relay the information to a group of serine/threonine protein kinases called CBL-interacting protein kinases (CIPKs). In this study, we found that a few CBL members can also target another group of enzymes 5'-methylthioadenosine nucleosidases (MTANs), which are encoded by two genes in Arabidopsis, AtMTAN1 and AtMTAN2. In the yeast two-hybrid system, AtMTAN1 interacted with multiple CBL members such as CBL2, CBL3 and CBL6, whereas AtMTAN2 associated exclusively with CBL3. We further demonstrated that the CBL3-AtMTAN2 association occurs in a calcium-dependent manner, which results in a significant decrease in the enzyme activity of the AtMTAN2 protein. Taken together, these results clearly indicate that the CBL family can target at least two distinct groups of enzymes (CIPKs and MTANs), conferring an additional level of complexity on the CBL-mediated signaling networks. In addition, our finding also provides a novel molecular mechanism by which calcium signals are transduced to alter metabolite profiles in plants.
authors.affiliation: Department of Molecular Biology, PERI, Sejong University, Seoul 143-747, Republic of Korea.
authors.forename: Sung Han
authors.initials: SH
authors.lastname: Ok
authors.affiliation: Department of Molecular Biology, PERI, Sejong University, Seoul 143-747, Republic of Korea.
authors.forename: Joo Hyuk
authors.initials: JH
authors.lastname: Cho
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Seung-Ick
authors.initials: SI
authors.lastname: Oh
authors.affiliation: Department of Molecular Biology, PERI, Sejong University, Seoul 143-747, Republic of Korea.
authors.forename: Mi Na
authors.initials: MN
authors.lastname: Choi
authors.affiliation: Department of Molecular Biology, PERI, Sejong University, Seoul 143-747, Republic of Korea.
authors.forename: Jae-Yeon
authors.initials: JY
authors.lastname: Ma
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Jeong-Sheop
authors.initials: JS
authors.lastname: Shin
authors.affiliation: Department of Molecular Biology, PERI, Sejong University, Seoul 143-747, Republic of Korea. Electronic address: knkim@sejong.ac.kr.
authors.forename: Kyung-Nam
authors.initials: KN
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D018076:DNA, Complementary / Q000302:isolation & purification; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D059828:Plant Cells / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D011683:Purine-Nucleoside Phosphorylase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C484079:CBL3 protein, Arabidopsis; D002135:Calcium-Binding Proteins; D018076:DNA, Complementary; D011683:Purine-Nucleoside Phosphorylase; C540168:MTAN1 protein, Arabidopsis; C540169:MTAN2 protein, Arabidopsis; D001616:beta-Galactosidase; D002118:Calcium
keywords: Arabidopsis; CBL; CIPK; Calcium signaling; MTAN