title: New insights into the dimerization of small GTPase Rac/ROP guanine nucleotide exchange factors in rice.
abstract: Molecular links between receptor-kinases and Rac/ROP family small GTPases mediated by activator guanine nucleotide exchange factors (GEFs) govern diverse biological processes. However, it is unclear how the Rac/ROP GTPases orchestrate such a wide variety of activities. Here, we show that rice OsRacGEF1 forms homodimers, and heterodimers with OsRacGEF2, at the plasma membrane (PM) and the endoplasmic reticulum (ER). OsRacGEF2 does not bind directly to the receptor-like kinase (RLK) OsCERK1, but forms a complex with OsCERK1 through OsRacGEF1 at the ER. This complex is transported from ER to the PM and there associates with OsRac1, resulting in the formation of a stable immune complex. Such RLK-GEF heterodimer complexes may explain the diversity of Rac/ROP family GTPase signalings.
authors.affiliation: a Laboratory of Plant Molecular Genetics; Graduate School of Biological Sciences; Nara Institute of Science and Technology ; Ikoma , Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Akamatsu
authors.forename: Kazumi
authors.initials: K
authors.lastname: Uno
authors.forename: Midori
authors.initials: M
authors.lastname: Kato
authors.forename: Hann Ling
authors.initials: HL
authors.lastname: Wong
authors.forename: Ko
authors.initials: K
authors.lastname: Shimamoto
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kawano
mesh_terms: D000595:Amino Acid Sequence; D005453:Fluorescence; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism*; D012275:Oryza / Q000166:cytology / Q000378:metabolism*; D059828:Plant Cells / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D010940:Plant Proteins; D020559:Monomeric GTP-Binding Proteins
keywords: PRONE GEF; Rac/ROP GTPase; dimerization; membrane trafficking