title: Actin-dependent deposition of putative endosomes and endoplasmic reticulum during early stages of wound healing in characean internodal cells.
abstract: We investigated the behaviour of organelles stained with FM1-43 (putative endosomes) and/or LysoTracker Red (LTred; acidic compartments) and of the endoplasmic reticulum (ER) during healing of puncture and UV-induced wounds in internodal cells of Nitella flexilis and Chara corallina. Immediately after puncture, wounds were passively sealed with a plug of solid vacuolar inclusions, onto which a bipartite wound wall was actively deposited. The outer, callose-containing amorphous layer consisted of remnants of FM1-43- and LTred-labelled organelles, ER cisternae and polysaccharide-containing secretory vesicles, which became deposited in the absence of membrane retrieval (compound exocytosis). During formation of the inner cellulosic layer, exocytosis of secretory vesicles with the newly formed plasma membrane is coupled to endocytosis via coated vesicles. Migration of FM1-43- and LTred-stained organelles, ER and secretory vesicles towards the cell cortex and deposition of a bipartite wound wall could also be induced by spot-like irradiation with ultraviolet light. Cytochalasin D reversibly inhibited the accumulation and deposition of organelles. Our study indicates that active actin-dependent deposition of putative recycling endosomes is required for wound healing (plasma membrane repair) and supports the hypothesis that deposition of ER cisternae helps to restore wounding-disturbed Ca(2+) metabolism.
authors.affiliation: Division of Plant Physiology, Department of Cell Biology, University of Salzburg, Hellbrunnerstrasse 34, Salzburg, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Klima
authors.forename: I
authors.initials: I
authors.lastname: Foissner
mesh_terms: D000199:Actins / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D022082:Cellular Structures / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism; D044784:Chara / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D015638:Cytochalasin D / Q000494:pharmacology; D004705:Endocytosis; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism*; D005089:Exocytosis; D044443:Nitella / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D010935:Plant Diseases; D011134:Polysaccharides / Q000378:metabolism; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D022142:Secretory Vesicles / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects; D014617:Vacuoles / Q000378:metabolism
chemical_list: D000199:Actins; C073804:FM1 43; D011134:Polysaccharides; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D015638:Cytochalasin D; D002482:Cellulose; D002118:Calcium