title: POM-POM2/cellulose synthase interacting1 is essential for the functional association of cellulose synthase and microtubules in Arabidopsis.
abstract: In plants, regulation of cellulose synthesis is fundamental for morphogenesis and plant growth. Cellulose is synthesized at the plasma membrane, and the orientation of synthesis is guided by cortical microtubules; however, the guiding mechanism is currently unknown. We show that the conditional root elongation pom2 mutants are impaired in cell elongation, fertility, and microtubule-related functions. Map-based cloning of the POM-POM2 locus revealed that it is allelic to CELLULOSE SYNTHASE INTERACTING1 (CSI1). Fluorescently tagged POM2/CSI1s associated with both plasma membrane-located cellulose synthases (CESAs) and post-Golgi CESA-containing compartments. Interestingly, while CESA insertions coincided with cortical microtubules in the pom2/csi1 mutants, the microtubule-defined movement of the CESAs was significantly reduced in the mutant. We propose that POM2/CSI1 provides a scaffold between the CESAs and cortical microtubules that guide cellulose synthesis.
authors.affiliation: Max-Planck-Institute for Molecular Plant Physiology, 14476 Potsdam, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bringmann
authors.forename: Eryang
authors.initials: E
authors.lastname: Li
authors.forename: Arun
authors.initials: A
authors.lastname: Sampathkumar
authors.forename: Tomas
authors.initials: T
authors.lastname: Kocabek
authors.forename: Marie-Theres
authors.initials: MT
authors.lastname: Hauser
authors.forename: Staffan
authors.initials: S
authors.lastname: Persson
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005298:Fertility / Q000235:genetics / Q000502:physiology; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C551801:CSI1 protein, Arabidopsis; D002352:Carrier Proteins; D005964:Glucosyltransferases; C063760:cellulose synthase (GDP-forming)