Functional Characterization of the KNOLLE-Interacting t-SNARE AtSNAP33 and Its Role in Plant Cytokinesis

• Published in: The Journal of cell biology Vol. 155; no. 2; pp. 239 - 249
• Main Authors: Heese, Maren, Gansel, Xavier, Sticher, Liliane, Wick, Peter, Grebe, Markus, Granier, Fabienne, Jürgens, Gerd
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 15-10-2001; The Rockefeller University Press
• Subjects: Amino Acid Sequence; Arabidopsis - anatomy & histology; Arabidopsis - cytology; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis Proteins - physiology; Carrier Proteins - genetics; Carrier Proteins - physiology; Cell Cycle Proteins; Cell Division; Cell membranes; Cellular biology; Cytokines; Cytokinesis; Daughter cells; Functions; Genomics; Intracellular Membranes - chemistry; Lesions; Life Sciences; Membrane Fusion; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membrane Proteins - physiology; Membranes; Molecular Sequence Data; Mutagenesis, Insertional; Mutation; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - physiology; Phenotype; Phenotypes; Plant growth; Plant Proteins; Plants; Qa-SNARE Proteins; Qb-SNARE Proteins; Qc-SNARE Proteins; Seedlings; Sequence Homology, Amino Acid; SNARE proteins; Synaptosomal-Associated Protein 25; Tissue Distribution; Two-Hybrid System Techniques; Vesicular Transport Proteins; Yeasts; LOCALISATION
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200107126

Cytokinesis requires membrane fusion during cleavage-furrow ingression in animals and cell plate formation in plants. In Arabidopsis, the Sec1 homologue KEULE (KEU) and the cytokinesis-specific syntaxin KNOLLE (KN) cooperate to promote vesicle fusion in the cell division plane. Here, we characterize AtSNAP33, an Arabidopsis homologue of the t-SNARE SNAP25, that was identified as a KN interactor in a yeast two-hybrid screen. AtSNAP33 is a ubiquitously expressed membrane-associated protein that accumulated at the plasma membrane and during cell division colocalized with KN at the forming cell plate. A T-DNA insertion in the AtSNAP33 gene caused loss of AtSNAP33 function, resulting in a lethal dwarf phenotype. atsnap33 plantlets gradually developed large necrotic lesions on cotyledons and rosette leaves, resembling pathogen-induced cellular responses, and eventually died before flowering. In addition, mutant seedlings displayed cytokinetic defects, and atsnap33 in combination with the cytokinesis mutant keu was embryo lethal. Analysis of the Arabidopsis genome revealed two further SNAP25-like proteins that also interacted with KN in the yeast two-hybrid assay. Our results suggest that AtSNAP33, the first SNAP25 homologue characterized in plants, is involved in diverse membrane fusion processes, including cell plate formation, and that AtSNAP33 function in cytokinesis may be replaced partially by other SNAP25 homologues.