title: GEM, a member of the GRAM domain family of proteins, is part of the ABA signaling pathway.
abstract: Abscisic acid (ABA) is fundamental for plant development. Multiple factors have been identified that participate in the ABA signaling network, although a role of many proteins still await to be demonstrated. Here we have investigated the role of GEM (GL2 EXPRESSION MODULATOR), originally annotated as an ABA-responsive protein. GEM contains a GRAM domain, a feature shared with other eight Arabidopsis proteins for which we propose the name of GRE (GEM-RELATED) proteins. We found that (i) GEM expression responds to ABA, (ii) its promoter contains ABRE sites required for ABA response, and (iii) GEM expression depends on members of the ABA signaling pathway. This is consistent with the expression pattern of GEM during development in plant locations were ABA is known to play a direct role. We also found that GEM binds various phospholipids, e.g. mono and diphosphates and phosphatidic acid, suggesting a potential link of GEM with membrane-associated processes. Consistent with this, we found that the phosphoinositol-4-phosphate kinase PIP5K9 binds GEM in vivo. Finally, we demonstrated a role of GEM in seed dormancy. Together, our data led us to propose that GEM is an ABA-responsive protein that may function downstream of ABI5 as part of the ABA signaling pathway.
authors.affiliation: Centro de Biologia Molecular Severo Ochoa (CSIC - UAM), Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Mauri
authors.affiliation: Centro de Biologia Molecular Severo Ochoa (CSIC - UAM), Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Fernández-Marcos
authors.affiliation: Centro de Biologia Molecular Severo Ochoa (CSIC - UAM), Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Celina
authors.initials: C
authors.lastname: Costas
authors.affiliation: Centro de Biologia Molecular Severo Ochoa (CSIC - UAM), Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Desvoyes
authors.affiliation: Centro de Biologia Molecular Severo Ochoa (CSIC - UAM), Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Pichel
authors.affiliation: Centro de Biologia Molecular Severo Ochoa (CSIC - UAM), Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Caro
authors.affiliation: Centro de Biologia Molecular Severo Ochoa (CSIC - UAM), Nicolas Cabrera 1, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Crisanto
authors.initials: C
authors.lastname: Gutierrez
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018506:Gene Expression Regulation, Plant; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; C520031:GEM protein, Arabidopsis; D047908:Intracellular Signaling Peptides and Proteins; D010743:Phospholipids; D000040:Abscisic Acid