Membrane fusion and the cell cycle: Cdc48p participates in the fusion of ER membranes.
The fusion of endoplasmic reticulum (ER) membranes in yeast is an essential process required for normal progression of the nuclear cell cycle, karyogamy, and the maintenance of an intact organellar compartment. We showed previously that this process requires a novel fusion machinery distinct from the classic membrane docking/fusion machinery containing Sec17p (alpha-SNAP) and Sec18p (NSF). Here we show that Cdc48p, a cell-cycle protein with homology to Sec18p, is required in ER fusion. A temperature-sensitive cdc48 mutant is conditionally defective in ER fusion in vitro. Addition of purified Cdc48p restores the fusion of isolated cdc48 mutant ER membranes. We propose that Cdc48p is part of an evolutionarily conserved fusion/docking machinery involved in multiple homotypic fusion events.
Latterich
M
M
Howard Hughes Medical Institute, University of California, Berkeley 94720, USA.
Fröhlich
K U
KU
Schekman
R
R
D000251:Adenosine Triphosphatases; D000818:Animals; D000918:Antibody Specificity; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000276:immunology / Q000502:physiology*; D003600:Cytosol / Q000502:physiology; D004721:Endoplasmic Reticulum / Q000502:physiology* / Q000648:ultrastructure; D005656:Fungal Proteins / Q000502:physiology*; D007425:Intracellular Membranes / Q000502:physiology; D008561:Membrane Fusion / Q000502:physiology*; D011817:Rabbits; D000074405:Valosin Containing Protein; D015003:Yeasts / Q000166:cytology
D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D000251:Adenosine Triphosphatases; D000074405:Valosin Containing Protein