title: Morlin, an inhibitor of cortical microtubule dynamics and cellulose synthase movement.
abstract: Morlin (7-ethoxy-4-methyl chromen-2-one) was discovered in a screen of 20,000 compounds for small molecules that cause altered cell morphology resulting in swollen root phenotype in Arabidopsis. Live-cell imaging of fluorescently labeled cellulose synthase (CESA) and microtubules showed that morlin acts on the cortical microtubules and alters the movement of CESA. Morlin caused a novel syndrome of cytoskeletal defects, characterized by cortical array reorientation and compromised rates of both microtubule elongation and shrinking. Formation of shorter and more bundled microtubules and detachment from the cell membrane resulted when GFP::MAP4-MBP was used to visualize microtubules during morlin treatment. Cytoskeletal effects were accompanied by a reduction in the velocity and redistribution of CESA complexes labeled with YFP::CESA6 at the cell cortex. Morlin caused no inhibition of mouse myoblast, bacterial or fungal cell proliferation at concentrations that inhibit plant cell growth. By contrast, morlin stimulated microtubule disassembly in cultured hippocampal neurons but had no significant effect on cell viability. Thus, morlin appears to be a useful new probe of the mechanisms that regulate microtubule cortical array organization and its functional interaction with CESA.
authors: Department of Plant Biology, Carnegie Institution, Stanford, CA 94305, USA.
authors: Seth
authors: S
authors: DeBolt
authors: Ryan
authors: R
authors: Gutierrez
authors: David W
authors: DW
authors: Ehrhardt
authors: Carlos V
authors: CV
authors: Melo
authors: Loretta
authors: L
authors: Ross
authors: Sean R
authors: SR
authors: Cutler
authors: Christopher
authors: C
authors: Somerville
authors: Dario
authors: D
authors: Bonetta
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D003374:Coumarins / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D005964:Glucosyltransferases / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007700:Kinetics; D018613:Microscopy, Confocal; D018715:Microscopy, Video; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects* / Q000378:metabolism; D008956:Models, Chemical; D015394:Molecular Structure
chemical_list: D003374:Coumarins; D004791:Enzyme Inhibitors; D008869:Microtubule-Associated Proteins; C519670:morlin; D049452:Green Fluorescent Proteins; D005964:Glucosyltransferases; C478648:cellulose synthase