title: Initiation of cell wall pattern by a Rho- and microtubule-driven symmetry breaking.
abstract: A specifically patterned cell wall is a determinant of plant cell shape. Yet, the precise mechanisms that underlie initiation of cell wall patterning remain elusive. By using a reconstitution assay, we revealed that ROPGEF4 (Rho of plant guanine nucleotide exchange factor 4) and ROPGAP3 [ROP guanosine triphosphatase (GTPase)-activating protein 3] mediate local activation of the plant Rho GTPase ROP11 to initiate distinct pattern of secondary cell walls in xylem cells. The activated ROP11 recruits MIDD1 to induce local disassembly of cortical microtubules. Conversely, cortical microtubules eliminate active ROP11 from the plasma membrane through MIDD1. Such a mutual inhibitory interaction between active ROP domains and cortical microtubules establishes the distinct pattern of secondary cell walls. This Rho-based regulatory mechanism shows how plant cells initiate and control cell wall patterns to form various cell shapes.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. oda@biol.s.u-tokyo.ac.jp
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Oda
authors.forename: Hiroo
authors.initials: H
authors.lastname: Fukuda
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D048430:Cell Shape; D002473:Cell Wall / Q000737:chemistry* / Q000201:enzymology; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000737:chemistry / Q000201:enzymology*; D017434:Protein Structure, Tertiary; D052584:Xylem / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology; D020741:rho GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D008869:Microtubule-Associated Proteins; C572956:ROPGEF4 protein, Arabidopsis; C572957:ROP11 protein, Arabidopsis; D020741:rho GTP-Binding Proteins