p47 is a cofactor for p97-mediated membrane fusion

At least two distinct ATPases, NSF and p97, are known to be involved in the heterotypic fusion of transport vesicles with their target membranes and the homotypic fusion of membrane compartments. The NSF-mediated fusion pathway is the best characterized, many of the components having been identified and their functions analysed. In contrast, none of the accessory proteins for the p97-mediated fusion pathway has been identified. Now we have identified the first such component, a protein of relative molecular mass 47,000 (p47), which forms a tight, stoichiometric complex with cytosolic p97 (one trimer of p47 per hexamer of p97). It is essential for the p97-mediated regrowth of Golgi cisternae from mitotic Golgi fragments, a process restricted to animal cells. As a homologue of p47 exists in budding yeast, this indicates that it might also be involved in other membrane fusion reactions catalysed by p97, such as karyogamy.

[1]  E. Dubois,et al.  Sequencing and functional analysis of a 32 560 bp segment on the left arm of yeast chromosome II. Identification of 26 open reading frames, including the KIP1 and SEC17 genes , 1993, Yeast.

[2]  G. Schiavo,et al.  Clostridial neurotoxins as tools to investigate the molecular events of neurotransmitter release. , 1994, Seminars in cell biology.

[3]  R. Schekman,et al.  Membrane fusion and the cell cycle: Cdc48p participates in the fusion of ER membranes , 1995, Cell.

[4]  Saxton.  Semper: Distortion Compensation, Selective Averaging, 3-D Reconstruction, and Transfer Function Correction in a Highly Programmable System , 1996, Journal of structural biology.

[5]  J R Yates,et al.  Protein sequencing by tandem mass spectrometry. , 1986, Proceedings of the National Academy of Sciences of the United States of America.

[6]  K. Arndt,et al.  The SIT4 protein phosphatase is required in late G1 for progression into S phase. , 1991, Cold Spring Harbor symposia on quantitative biology.

[7]  J. Rothman,et al.  Implications of the SNARE hypothesis for intracellular membrane topology and dynamics , 1994, Current Biology.

[8]  J. Peters,et al.  An NSF-like ATPase, p97, and NSF mediate cisternal regrowth from mitotic golgi fragments , 1995, Cell.

[9]  G. Warren,et al.  Membrane partitioning during cell division. , 1993, Annual review of biochemistry.

[10]  J. Peters,et al.  An abundant and ubiquitous homo‐oligomeric ring‐shaped ATPase particle related to the putative vesicle fusion proteins Sec18p and NSF. , 1990, The EMBO journal.

[11]  M. Carlson,et al.  Protein phosphatase type 1 interacts with proteins required for meiosis and other cellular processes in Saccharomyces cerevisiae , 1996, Molecular and cellular biology.

[12]  F. Confalonieri,et al.  SAV, an archaebacterial gene with extensive homology to a family of highly conserved eukaryotic ATPases. , 1994, Journal of molecular biology.

[13]  W. Balch,et al.  GTPases: multifunctional molecular switches regulating vesicular traffic. , 1994, Annual review of biochemistry.

[14]  D. Botstein,et al.  Yeast cell cycle protein CDC48p shows full-length homology to the mammalian protein VCP and is a member of a protein family involved in secretion, peroxisome formation, and gene expression , 1991, The Journal of cell biology.

[15]  J. Harris,et al.  Ubiquitous soluble Mg(2+)-ATPase complex. A structural study. , 1992, Journal of molecular biology.

[16]  U. Acharya,et al.  The formation of golgi stacks from vesiculated golgi membranes requires two distinct fusion events , 1995, Cell.

[17]  R. Schekman,et al.  Vesicle-mediated protein sorting. , 1992, Annual review of biochemistry.

[18]  J. Rothman,et al.  Protein Sorting by Transport Vesicles , 1996, Science.

[19]  S. Pfeffer.  Transport vesicle docking: SNAREs and associates. , 1996, Annual review of cell and developmental biology.

[20]  T. Misteli,et al.  Reassembly of Golgi stacks from mitotic Golgi fragments in a cell-free system , 1995, The Journal of cell biology.

[21]  F. Volkert,et al.  The Saccharomyces SHP1 gene, which encodes a regulator of phosphoprotein phosphatase 1 with differential effects on glycogen metabolism, meiotic differentiation, and mitotic cell cycle progression , 1995, Molecular and cellular biology.

[22]  Reinhard Jahn,et al.  Vesicle fusion from yeast to man , 1994, Nature.

[23]  D. Pappin,et al.  Identification of myocardial proteins from two‐dimensional gels by peptide mass fingerprinting , 1995, Electrophoresis.

[24]  R. Aebersold,et al.  Functionalized membrane supports for covalent protein microsequence analysis. , 1991, Analytical biochemistry.