scholarly journals Alternative Modes of Organellar Segregation during Sporulation in Saccharomyces cerevisiae

2007 ◽  
Vol 6 (11) ◽  
pp. 2009-2017 ◽  
Author(s):  
Yasuyuki Suda ◽  
Hideki Nakanishi ◽  
Erin M. Mathieson ◽  
Aaron M. Neiman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Cell Division ◽  
Plasma Membranes ◽  
De Novo ◽  
Leading Edge ◽  
Protein Coat ◽  
Prospore Membrane ◽  
Cortical Endoplasmic Reticulum ◽  
Mitotic Cells

ABSTRACT Formation of ascospores in the yeast Saccharomyces cerevisiae is driven by an unusual cell division in which daughter nuclei are encapsulated within de novo-formed plasma membranes, termed prospore membranes. Generation of viable spores requires that cytoplasmic organelles also be captured along with nuclei. In mitotic cells segregation of mitochondria into the bud requires a polarized actin cytoskeleton. In contrast, genes involved in actin-mediated transport are not essential for sporulation. Instead, efficient segregation of mitochondria into spores requires Ady3p, a component of a protein coat found at the leading edge of the prospore membrane. Other organelles whose mitotic segregation is promoted by actin, such as the vacuole and the cortical endoplasmic reticulum, are not actively segregated during sporulation but are regenerated within spores. These results reveal that organellar segregation into spores is achieved by mechanisms distinct from those in mitotic cells.

Ady3p Links Spindle Pole Body Function to Spore Wall Synthesis in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1439-1450
Author(s):  
Mark E Nickas ◽  
Aaron M Neiman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Spindle Pole Body ◽  
Leading Edge ◽  
Spindle Pole ◽  
Spore Wall ◽  
Pole Body ◽  
Prospore Membrane ◽  
Sporulation Efficiency ◽  
Spore Walls

Abstract Spore formation in Saccharomyces cerevisiae requires the de novo synthesis of prospore membranes and spore walls. Ady3p has been identified as an interaction partner for Mpc70p/Spo21p, a meiosis-specific component of the outer plaque of the spindle pole body (SPB) that is required for prospore membrane formation, and for Don1p, which forms a ring-like structure at the leading edge of the prospore membrane during meiosis II. ADY3 expression has been shown to be induced in midsporulation. We report here that Ady3p interacts with additional components of the outer and central plaques of the SPB in the two-hybrid assay. Cells that lack ADY3 display a decrease in sporulation efficiency, and most ady3Δ/ady3Δ asci that do form contain fewer than four spores. The sporulation defect in ady3Δ/ady3Δ cells is due to a failure to synthesize spore wall polymers. Ady3p forms ring-like structures around meiosis II spindles that colocalize with those formed by Don1p, and Don1p rings are absent during meiosis II in ady3Δ/ady3Δ cells. In mpc70Δ/mpc70Δ cells, Ady3p remains associated with SPBs during meiosis II. Our results suggest that Ady3p mediates assembly of the Don1p-containing structure at the leading edge of the prospore membrane via interaction with components of the SPB and that this structure is involved in spore wall formation.

scholarly journals The Anaphase Promoting Complex Targeting Subunit Ama1 Links Meiotic Exit to Cytokinesis during Sporulation inSaccharomyces cerevisiae

2009 ◽  
Vol 20 (1) ◽  
pp. 134-145 ◽  
Author(s):  
Aviva E. Diamond ◽  
Jae-Sook Park ◽  
Ichiro Inoue ◽  
Hiroyuki Tachikawa ◽  
Aaron M. Neiman
Keyword(s):  
Cell Division ◽  
Plasma Membranes ◽  
Leading Edge ◽  
Phosphorylation Sites ◽  
Cyclin Dependent Kinase ◽  
Anaphase Promoting Complex ◽  
Prospore Membrane ◽  
A Cell ◽  
Essential Function ◽  
Kinase Phosphorylation

Ascospore formation in yeast is accomplished through a cell division in which daughter nuclei are engulfed by newly formed plasma membranes, termed prospore membranes. Closure of the prospore membrane must be coordinated with the end of meiosis II to ensure proper cell division. AMA1 encodes a meiosis-specific activator of the anaphase promoting complex (APC). The activity of APCAma1is inhibited before meiosis II, but the substrates specifically targeted for degradation by Ama1 at the end of meiosis are unknown. We show here that ama1Δ mutants are defective in prospore membrane closure. Ssp1, a protein found at the leading edge of the prospore membrane, is stabilized in ama1Δ mutants. Inactivation of a conditional form of Ssp1 can partially rescue the sporulation defect of the ama1Δ mutant, indicating that an essential function of Ama1 is to lead to the removal of Ssp1. Depletion of Cdc15 causes a defect in meiotic exit. We find that prospore membrane closure is also defective in Cdc15 and that this defect can be overcome by expression of a form of Ama1 in which multiple consensus cyclin-dependent kinase phosphorylation sites have been mutated. These results demonstrate that APCAma1functions to coordinate the exit from meiosis II with cytokinesis.

scholarly journals The Smk1 MAPK and Its Activator, Ssp2, Are Required for Late Prospore Membrane Development in Sporulating Saccharomyces cerevisiae

2021 ◽  
Vol 7 (1) ◽  
pp. 53
Author(s):  
Matthew Durant ◽  
Joseph M. Roesner ◽  
Xheni Mucelli ◽  
Christian J. Slubowski ◽  
Erin Klee ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Plasma Membrane ◽  
Map Kinase ◽  
De Novo ◽  
Leading Edge ◽  
Spore Wall ◽  
Yeast Saccharomyces Cerevisiae ◽  
Prospore Membrane ◽  
Membrane Compartments ◽  
Membrane Development

During sporulation in the budding yeast Saccharomyces cerevisiae, proper development of the prospore membrane is necessary for the formation of viable spores. The prospore membrane will eventually become the plasma membrane of the newly formed haploid spore and also serves as the template for the deposition of the spore wall. The prospore membrane is generated de novo during meiosis II and the growing edge of the prospore membrane is associated with the Leading Edge Protein (LEP) complex. We find that the Smk1 MAP kinase, along with its activator Ssp2, transiently localizes with the LEP during late meiosis II. SSP2 is required for the leading edge localization of Smk1; this localization is independent of the activation state of Smk1. Like other LEP components, the localization of Smk1 at the leading edge also depends on Ady3. Although prospore membrane development begins normally in smk1 and ssp2 mutants, late prospore membrane formation is disrupted, with the formation of ectopic membrane compartments. Thus, MAP kinase signaling plays an important role in the formation of the prospore membrane.

scholarly journals Prospore Membrane Formation Defines a Developmentally Regulated Branch of the Secretory Pathway in Yeast

1998 ◽  
Vol 140 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Aaron M. Neiman
Keyword(s):  
Cell Division ◽  
Mother Cell ◽  
Plasma Membranes ◽  
Secretory Pathway ◽  
De Novo ◽  
Extracellular Proteins ◽  
Spore Formation ◽  
Electron Microscopic ◽  
Developmentally Regulated ◽  
Prospore Membrane

Spore formation in yeast is an unusual form of cell division in which the daughter cells are formed within the mother cell cytoplasm. This division requires the de novo synthesis of a membrane compartment, termed the prospore membrane, which engulfs the daughter nuclei. The effect of mutations in late-acting genes on sporulation was investigated. Mutation of SEC1, SEC4, or SEC8 blocked spore formation, and electron microscopic analysis of the sec4-8 mutant indicated that this inability to produce spores was caused by a failure to form the prospore membrane. The soluble NSF attachment protein 25 (SNAP-25) homologue SEC9, by contrast, was not required for sporulation. The absence of a requirement for SEC9 was shown to be due to the sporulation-specific induction of a second, previously undescribed, SNAP-25 homologue, termed SPO20. These results define a developmentally regulated branch of the secretory pathway and suggest that spore morphogenesis in yeast proceeds by the targeting and fusion of secretory vesicles to form new plasma membranes in the interior of the mother cell. Consistent with this model, the extracellular proteins Gas1p and Cts1p were localized to an internal compartment in sporulating cells. Spore formation in yeast may be a useful model for understanding secretion-driven cell division events in a variety of plant and animal systems.

scholarly journals Dynamic localization of a yeast development–specific PP1 complex during prospore membrane formation is dependent on multiple localization signals and complex formation

2017 ◽  
Vol 28 (26) ◽  
pp. 3881-3895 ◽  
Author(s):  
Tsuyoshi S. Nakamura ◽  
Yumi Numajiri ◽  
Yuuya Okumura ◽  
Junji Hidaka ◽  
Takayuki Tanaka ◽  
...  
Keyword(s):  
Plasma Membranes ◽  
De Novo ◽  
Developmental Process ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Membrane Structures ◽  
Prospore Membrane ◽  
Membrane Extension ◽  
And Function

During the developmental process of sporulation in Saccharomyces cerevisiae, membrane structures called prospore membranes are formed de novo, expand, extend, acquire a round shape, and finally become plasma membranes of the spores. GIP1 encodes a regulatory/targeting subunit of protein phosphatase type 1 that is required for sporulation. Gip1 recruits the catalytic subunit Glc7 to septin structures that form along the prospore membrane; however, the molecular basis of its localization and function is not fully understood. Here we show that Gip1 changes its localization dynamically and is required for prospore membrane extension. Gip1 first associates with the spindle pole body as the prospore membrane forms, moves onto the prospore membrane and then to the septins as the membrane extends, distributes around the prospore membrane after closure, and finally translocates into the nucleus in the maturing spore. Deletion and mutation analyses reveal distinct sequences in Gip1 that are required for different localizations and for association with Glc7. Binding to Glc7 is also required for proper localization. Strikingly, localization to the prospore membrane, but not association with septins, is important for Gip1 function. Further, our genetic analysis suggests that a Gip1–Glc7 phosphatase complex regulates prospore membrane extension in parallel to the previously reported Vps13, Spo71, Spo73 pathway.

scholarly journals SPO71 Encodes a Developmental Stage-Specific Partner for Vps13 in Saccharomyces cerevisiae

2013 ◽  
Vol 12 (11) ◽  
pp. 1530-1537 ◽  
Author(s):  
Jae-Sook Park ◽  
Yuuya Okumura ◽  
Hiroyuki Tachikawa ◽  
Aaron M. Neiman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Ectopic Expression ◽  
Membrane Vesicles ◽  
Specific Gene ◽  
Wild Type ◽  
Protein Mutation ◽  
Prospore Membrane ◽  
In The Wild ◽  
Membrane Morphogenesis

ABSTRACT The creation of haploid gametes in yeast, termed spores, requires the de novo formation of membranes within the cytoplasm. These membranes, called prospore membranes, enclose the daughter nuclei generated by meiosis. Proper growth and closure of prospore membranes require the highly conserved Vps13 protein. Mutation of SPO71 , a meiosis-specific gene first identified as defective in spore formation, was found to display defects in membrane morphogenesis very similar to those seen in vps13 Δ cells. Specifically, prospore membranes are smaller than in the wild type, they fail to close, and membrane vesicles are present within the prospore membrane lumen. As in vps13 Δ cells, the levels of phophatidylinositol-4-phosphate are reduced in the prospore membranes of spo71 Δ cells. SPO71 is required for the translocation of Vps13 from the endosome to the prospore membrane, and ectopic expression of SPO71 in vegetative cells results in mislocalization of Vps13. Finally, the two proteins can be coprecipitated from sporulating cells. We propose that Spo71 is a sporulation-specific partner for Vps13 and that they act in concert to regulate prospore membrane morphogenesis.

scholarly journals Different polarisome components play distinct roles in Slt2p-regulated cortical ER inheritance in Saccharomyces cerevisiae

2013 ◽  
Vol 24 (19) ◽  
pp. 3145-3154 ◽  
Author(s):  
Xia Li ◽  
Susan Ferro-Novick ◽  
Peter Novick
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Protein Kinase ◽  
Protein Phosphatase ◽  
Mitogen Activated Protein Kinase ◽  
Common Mechanism ◽  
Late Step ◽  
Mitogen Activated Protein ◽  
Cortical Endoplasmic Reticulum

Ptc1p, a type 2C protein phosphatase, is required for a late step in cortical endoplasmic reticulum (cER) inheritance in Saccharomyces cerevisiae. In ptc1Δ cells, ER tubules migrate from the mother cell and contact the bud tip, yet fail to spread around the bud cortex. This defect results from the failure to inactivate a bud tip–associated pool of the cell wall integrity mitogen-activated protein kinase, Slt2p. Here we report that the polarisome complex affects cER inheritance through its effects on Slt2p, with different components playing distinct roles: Spa2p and Pea2p are required for Slt2p retention at the bud tip, whereas Bni1p, Bud6p, and Sph1p affect the level of Slt2p activation. Depolymerization of actin relieves the ptc1Δ cER inheritance defect, suggesting that in this mutant the ER becomes trapped on the cytoskeleton. Loss of Sec3p also blocks ER inheritance, and, as in ptc1Δ cells, this block is accompanied by activation of Slt2p and is reversed by depolymerization of actin. Our results point to a common mechanism for the regulation of ER inheritance in which Slt2p activity at the bud tip controls the association of the ER with the actin-based cytoskeleton.

scholarly journals mRNAs Encoding Polarity and Exocytosis Factors Are Cotransported with the Cortical Endoplasmic Reticulum to the Incipient Bud in Saccharomyces cerevisiae

2007 ◽  
Vol 27 (9) ◽  
pp. 3441-3455 ◽  
Author(s):  
Stella Aronov ◽  
Rita Gelin-Licht ◽  
Gadi Zipor ◽  
Liora Haim ◽  
Einat Safran ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Nuclear Division ◽  
Mrna Localization ◽  
Dependent Manner ◽  
Protein Enrichment ◽  
Bud Emergence ◽  
Bud Site ◽  
Cortical Endoplasmic Reticulum ◽  
Asymmetrically Distributed

ABSTRACT Polarized growth in the budding yeast Saccharomyces cerevisiae depends upon the asymmetric localization and enrichment of polarity and secretion factors at the membrane prior to budding. We examined how these factors (i.e., Cdc42, Sec4, and Sro7) reach the bud site and found that their respective mRNAs localize to the tip of the incipient bud prior to nuclear division. Asymmetric mRNA localization depends upon factors that facilitate ASH1 mRNA localization (e.g., the 3′ untranslated region, She proteins 1 to 5, Puf6, actin cytoskeleton, and a physical association with She2). mRNA placement precedes protein enrichment and subsequent bud emergence, implying that mRNA localization contributes to polarization. Correspondingly, mRNAs encoding proteins which are not asymmetrically distributed (i.e., Snc1, Mso1, Tub1, Pex3, and Oxa1) are not polarized. Finally, mutations which affect cortical endoplasmic reticulum (ER) entry and anchoring in the bud (myo4Δ, sec3Δ, and srp101) also affect asymmetric mRNA localization. Bud-localized mRNAs, including ASH1, were found to cofractionate with ER microsomes in a She2- and Sec3-dependent manner; thus, asymmetric mRNA transport and cortical ER inheritance are connected processes in yeast.

Aux1p/Swa2p Is Required for Cortical Endoplasmic Reticulum Inheritance in Saccharomyces cerevisiae

2001 ◽  
Vol 12 (9) ◽  
pp. 2614-2628 ◽  
Author(s):  
Yunrui Du ◽  
Marc Pypaert ◽  
Peter Novick ◽  
Susan Ferro-Novick
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Fluorescent Protein ◽  
Yeast Saccharomyces Cerevisiae ◽  
Bifunctional Protein ◽  
Daughter Cells ◽  
Bud Neck ◽  
J Domain ◽  
Green Fluorescent ◽  
Cortical Endoplasmic Reticulum

In the yeast Saccharomyces cerevisiae, the endoplasmic reticulum (ER) is found at the periphery of the cell and around the nucleus. The segregation of ER through the mother-bud neck may occur by more than one mechanism because perinuclear, but not peripheral ER, requires microtubules for this event. To identify genes whose products are required for cortical ER inheritance, we have used a Tn3-based transposon library to mutagenize cells expressing a green fluorescent protein-tagged ER marker protein (Hmg1p). This approach has revealed that AUX1/SWA2plays a role in ER inheritance. The COOH terminus of Aux1p/Swa2p contains a J-domain that is highly related to the J-domain of auxilin, which stimulates the uncoating of clathrin-coated vesicles. Deletion of the J-domain of Aux1p/Swa2p leads to vacuole fragmentation and membrane accumulation but does not affect the migration of peripheral ER into daughter cells. These findings suggest that Aux1p/Swa2p may be a bifunctional protein with roles in membrane traffic and cortical ER inheritance. In support of this hypothesis, we find that Aux1p/Swa2p localizes to ER membranes.

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