Poster: Cell Cycle & Cytokinesis
Abs #
1098: Patellin, a sec14p-like protein, is localized to the cell plate
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Presenter: |
Peterman, T. Kaye , kpeterman@wellesley.edu |
Authors | Peterman, T. Kaye (A) Ohol, Yamini (A) | | Affiliations: |
(A): Wellesley College, Department of Biological Sciences
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During plant cytokinesis, the phragmoplast guides Golgi-derived vesicles to the plane of division where they fuse to initiate formation of the cell plate. We report here that patellin, a protein identified during a biochemical screen for F-actin-binding proteins, is associated with cytoplasmic puncta that resemble Golgi bodies and immunolocalizes to the expanding and maturing cell plate. In dividing BY2 cells immunolabeling was absent from the division zone at metaphase and early anaphase but appeared during telophase in the developing plate. Staining persisted for a time after the completion of cytokinesis, consistent with a role for patellin in the expansion and maturation stages of cell plate development. A similar pattern was observed in Arabidopsis root tips, where labeling was concentrated in the zone of cell division. Patellin, is one of a small family of proteins in Arabidopsis that consists of a variable N-terminal domain followed by a Sec14p-like lipid-binding pocket and a conserved C-terminal domain. Sec14p is a PtdIns/PtdCh transfer protein that functions during vesicle formation from the trans-Golgi network and is essential for protein secretion in S. cerevisiae. Biochemical fractionation studies indicated that patellin, like Sec14p, is a peripheral membrane protein. Given its similarity to Sec14p we tested bacterially expressed patellin for phospholipid binding activity using both lipid blot overlay and vesicle binding assays. Specific binding to the phosphoinositides, PtdIns-3-P, PtdIns-5-P and PtdIns-4,5-P2 was detected indicating that the biochemical properties of patellin are related to but distinct from those of Sec14p. We propose that patellin plays a role in vesicle trafficking events during cell plate expansion and maturation.
