Faculty Opinions recommendation of 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.

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Characterization of spindle pole body duplication reveals a regulatory role for nuclear pore complexes

The Journal of Cell Biology ◽

10.1083/jcb.201612129 ◽

2017 ◽

Vol 216 (8) ◽

pp. 2425-2442 ◽

Cited By ~ 19

Author(s):

Diana Rüthnick ◽

Annett Neuner ◽

Franziska Dietrich ◽

Daniel Kirrmaier ◽

Ulrike Engel ◽

...

Keyword(s):

Spindle Pole Body ◽

Spindle Pole ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Pole Body ◽

Associated Proteins ◽

Pore Complexes ◽

Open Question ◽

Cytoplasmic Side

The spindle pole body (SPB) of budding yeast duplicates once per cell cycle. In G1, the satellite, an SPB precursor, assembles next to the mother SPB (mSPB) on the cytoplasmic side of the nuclear envelope (NE). How the growing satellite subsequently inserts into the NE is an open question. To address this, we have uncoupled satellite growth from NE insertion. We show that the bridge structure that separates the mSPB from the satellite is a distance holder that prevents deleterious fusion of both structures. Binding of the γ-tubulin receptor Spc110 to the central plaque from within the nucleus is important for NE insertion of the new SPB. Moreover, we provide evidence that a nuclear pore complex associates with the duplicating SPB and helps to insert the SPB into the NE. After SPB insertion, membrane-associated proteins including the conserved Ndc1 encircle the SPB and retain it within the NE. Thus, uncoupling SPB growth from NE insertion unmasks functions of the duplication machinery.

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A Novel Allele of Saccharomyces cerevisiae NDC1 Reveals a Potential Role for the Spindle Pole Body Component Ndc1p in Nuclear Pore Assembly

Eukaryotic Cell ◽

10.1128/ec.3.2.447-458.2004 ◽

2004 ◽

Vol 3 (2) ◽

pp. 447-458 ◽

Cited By ~ 42

Author(s):

Corine K. Lau ◽

Thomas H. Giddings ◽

Mark Winey

Keyword(s):

Saccharomyces Cerevisiae ◽

Nuclear Envelope ◽

Protein Import ◽

Spindle Pole Body ◽

Spindle Pole ◽

Yeast Cells ◽

Nuclear Pore ◽

Restrictive Temperature ◽

Double Mutation ◽

Pole Body

ABSTRACT Both the spindle pole body (SPB) and the nuclear pore complex (NPC) are essential organelles embedded in the nuclear envelope throughout the life cycle of the budding yeast Saccharomyces cerevisiae. However, the mechanism by which these two multisubunit structures are inserted into the nuclear envelope during their biogenesis is not well understood. We have previously shown that Ndc1p is the only known integral membrane protein that localizes to both the SPBs and the NPCs and is required for SPB duplication. For this study, we generated a novel temperature-sensitive (ts) allele of NDC1 to investigate the role of Ndc1p at the NPCs. Yeast cells carrying this allele (ndc1-39) failed to insert the SPB into the nuclear envelope at the restrictive temperature. Importantly, the double mutation of ndc1-39 and NPC assembly mutant nic96-1 resulted in cells with enhanced growth defects. While nuclear protein import and NPC distribution in the nuclear envelope were unaffected, ndc1-39 mutants failed to properly incorporate the nucleoporin Nup49p into NPCs. These results provide evidence that Ndc1p is required for NPC assembly in addition to its role in SPB duplication. We postulate that Ndc1p is crucial for the biogenesis of both the SPBs and the NPCs at the step of insertion into the nuclear envelope.

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