The nuclear pore complex-associated protein, Mlp2p, binds to the yeast spindle pole body and promotes its efficient assembly.
The two yeast proteins Mlp1p and Mlp2p (homologues of the vertebrate protein Tpr) are filamentous proteins attached to the nuclear face of nuclear pore complexes. Here we perform a proteomic analysis, which reveals that the two Mlps have strikingly different interacting partners, testifying to their different roles within the cell. We find that Mlp2p binds directly to Spc110p, Spc42p, and Spc29p, which are three core components of the spindle pole body (SPB), the nuclear envelope-associated yeast spindle organizer. We further show that SPB function is compromised in mlp2 mutants. Cells lacking Mlp2p form significantly smaller SPBs, accumulate aberrant SPB component-containing structures inside the nucleus, and have stochastic failures of cell division. In addition, depletion of Mlp2p is synthetically lethal with mutants impaired in SPB assembly. Based on these data, we propose that Mlp2p links the SPB to the peripheral Mlp assembly, and that this linkage is required for efficient incorporation of components into the SPB.
Niepel
Mario
M
The Rockefeller University, New York, NY 10021, USA.
Strambio-de-Castillia
Caterina
C
Fasolo
Joseph
J
Chait
Brian T
BT
Rout
Michael P
MP
D002148:Calmodulin-Binding Proteins; D002467:Cell Nucleus / Q000502:physiology / Q000648:ultrastructure; D048749:Cytokinesis / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004256:DNA Polymerase I / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D013058:Mass Spectrometry; D008677:Metaphase; D046529:Microscopy, Electron, Transmission; D022101:Microtubule-Organizing Center / Q000648:ultrastructure; D009154:Mutation; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure
D002148:Calmodulin-Binding Proteins; D003598:Cytoskeletal Proteins; C119200:MLP2 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; C073277:SPC110 protein, S cerevisiae; C432692:SPC42 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D004256:DNA Polymerase I; D004259:DNA-Directed DNA Polymerase; C068352:MIP1 protein, S cerevisiae