Control of the terminal step of intracellular membrane fusion by protein phosphatase 1.

Intracellular membrane fusion is crucial for the biogenesis and maintenance of cellular compartments, for vesicular traffic between them, and for exo- and endocytosis. Parts of the molecular machinery underlying this process have been identified, but most of these components operate in mutual recognition of the membranes. Here it is shown that protein phosphatase 1 (PP1) is essential for bilayer mixing, the last step of membrane fusion. PP1 was also identified in a complex that contained calmodulin, the second known factor implicated in the regulation of bilayer mixing. The PP1-calmodulin complex was required at multiple sites of intracellular trafficking; hence, PP1 may be a general factor controlling membrane bilayer mixing.

[1]  S. Pfeffer.  Transport-vesicle targeting: tethers before SNAREs , 1999, Nature Cell Biology.

[2]  T. Nilsson,et al.  Cytosolic ATPases, p97 and NSF, are sufficient to mediate rapid membrane fusion , 1999, The EMBO journal.

[3]  Jens R. Coorssen,et al.  Biochemical and Functional Studies of Cortical Vesicle Fusion: The SNARE Complex and Ca2+ Sensitivity , 1998, The Journal of cell biology.

[4]  W. Wickner,et al.  Defining the functions of trans-SNARE pairs , 1998, Nature.

[5]  A. Mayer,et al.  Ca2+/calmodulin signals the completion of docking and triggers a late step of vacuole fusion , 1998, Nature.

[6]  M. Lindau,et al.  Fusion pore expansion in horse eosinophils is modulated by Ca2+ and protein kinase C via distinct mechanisms , 1998, The EMBO journal.

[7]  P. Philippsen,et al.  Additional modules for versatile and economical PCR‐based gene deletion and modification in Saccharomyces cerevisiae , 1998, Yeast.

[8]  W. Wickner,et al.  LMA1 Binds to Vacuoles at Sec18p (NSF), Transfers upon ATP Hydrolysis to a t-SNARE (Vam3p) Complex, and Is Released during Fusion , 1998, Cell.

[9]  Benedikt Westermann,et al.  SNAREpins: Minimal Machinery for Membrane Fusion , 1998, Cell.

[10]  M. Zerial,et al.  The diversity of Rab proteins in vesicle transport. , 1997, Current opinion in cell biology.

[11]  H. Pelham,et al.  Homotypic vacuolar fusion mediated by t- and v-SNAREs , 1997, Nature.

[12]  A. Mayer,et al.  Docking of Yeast Vacuoles Is Catalyzed by the Ras-like GTPase Ypt7p after Symmetric Priming by Sec18p (NSF) , 1997, The Journal of cell biology.

[13]  E. Muller,et al.  A Heterodimer of Thioredoxin and IB 2 Cooperates with Sec18p (NSF) to Promote Yeast Vacuole Inheritance , 1997, The Journal of cell biology.

[14]  A. Podtelejnikov,et al.  Linking genome and proteome by mass spectrometry: large-scale identification of yeast proteins from two dimensional gels. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[15]  M. Stark,et al.  Yeast Protein Serine/Threonine Phosphatases: Multiple Roles and Diverse Regulation , 1996, Yeast.

[16]  A. Mayer,et al.  Sec18p (NSF)-Driven Release of Sec17p (α-SNAP) Can Precede Docking and Fusion of Yeast Vacuoles , 1996, Cell.

[17]  A. Shevchenko,et al.  Mass spectrometric sequencing of proteins silver-stained polyacrylamide gels. , 1996, Analytical chemistry.

[18]  A. Podtelejnikov,et al.  Delayed extraction improves specificity in database searches by matrix-assisted laser desorption/ionization peptide maps. , 1996, Rapid communications in mass spectrometry : RCM.

[19]  H. Tung,et al.  Regulation of chromosome segregation by Glc8p, a structural homolog of mammalian inhibitor 2 that functions as both an activator and an inhibitor of yeast protein phosphatase 1 , 1995, Molecular and cellular biology.

[20]  M. Stark,et al.  The Saccharomyces cerevisiae gene SDS22 encodes a potential regulator of the mitotic function of yeast type 1 protein phosphatase , 1995, Molecular and cellular biology.

[21]  S. Emr,et al.  A new vital stain for visualizing vacuolar membrane dynamics and endocytosis in yeast , 1995, The Journal of cell biology.

[22]  S. Emr,et al.  Receptor-mediated protein sorting to the vacuole in yeast: roles for a protein kinase, a lipid kinase and GTP-binding proteins. , 1995, Annual review of cell and developmental biology.

[23]  C. MacKintosh,et al.  Purification of type 1 protein (serine/threonine) phosphatases by microcystin‐Sepharose affinity chromatography , 1994, FEBS letters.

[24]  W. Wickner,et al.  Determination of four biochemically distinct, sequential stages during vacuole inheritance in vitro , 1994, The Journal of cell biology.