Evidence that a septin diffusion barrier is dispensable for cytokinesis in budding yeast

2011 ◽  
Vol 392 (8-9) ◽  
pp. 813-829 ◽  
Author(s):  
Carsten Wloka ◽  
Ryuichi Nishihama ◽  
Masayuki Onishi ◽  
Younghoon Oh ◽  
Julia Hanna ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Trafficking ◽  
Diffusion Barrier ◽  
Synergistic Effects ◽  
Diffusion Barriers ◽  
Extracellular Matrix Remodeling ◽  
Matrix Remodeling ◽  
Double Ring ◽  
Division Site ◽  
Bud Neck

AbstractSeptins are essential for cytokinesis inSaccharomyces cerevisiae, but their precise roles remain elusive. Currently, it is thought that before cytokinesis, the hourglass-shaped septin structure at the mother-bud neck acts as a scaffold for assembly of the actomyosin ring (AMR) and other cytokinesis factors. At the onset of cytokinesis, the septin hourglass splits to form a double ring that sandwiches the AMR and may function as diffusion barriers to restrict diffusible cytokinesis factors to the division site. Here, we show that in cells lacking the septin Cdc10 or the septin-associated protein Bud4, the septins form a ring-like structure at the mother-bud neck that fails to re-arrange into a double ring early in cytokinesis. Strikingly, AMR assembly and constriction, the localization of membrane-trafficking and extracellular-matrix-remodeling factors, cytokinesis, and cell-wall-septum formation all occur efficiently incdc10Δandbud4Δmutants. Thus, diffusion barriers formed by the septin double ring do not appear to be critical forS. cerevisiaecytokinesis. However, an AMR mutation and a septin mutation have synergistic effects on cytokinesis and the localization of cytokinesis proteins, suggesting that tethering to the AMR and a septin diffusion barrier may function redundantly to localize proteins to the division site.

scholarly journals Biphasic targeting and cleavage furrow ingression directed by the tail of a myosin II

2010 ◽  
Vol 191 (7) ◽  
pp. 1333-1350 ◽  
Author(s):  
Xiaodong Fang ◽  
Jianying Luo ◽  
Ryuichi Nishihama ◽  
Carsten Wloka ◽  
Christopher Dravis ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Trafficking ◽  
Myosin Ii ◽  
Force Generation ◽  
Extracellular Matrix Remodeling ◽  
Cleavage Furrow ◽  
Matrix Remodeling ◽  
Division Site ◽  
Targeting Signals

Cytokinesis in animal and fungal cells utilizes a contractile actomyosin ring (AMR). However, how myosin II is targeted to the division site and promotes AMR assembly, and how the AMR coordinates with membrane trafficking during cytokinesis, remains poorly understood. Here we show that Myo1 is a two-headed myosin II in Saccharomyces cerevisiae, and that Myo1 localizes to the division site via two distinct targeting signals in its tail that act sequentially during the cell cycle. Before cytokinesis, Myo1 localization depends on the septin-binding protein Bni5. During cytokinesis, Myo1 localization depends on the IQGAP Iqg1. We also show that the Myo1 tail is sufficient for promoting the assembly of a “headless” AMR, which guides membrane deposition and extracellular matrix remodeling at the division site. Our study establishes a biphasic targeting mechanism for myosin II and highlights an underappreciated role of the AMR in cytokinesis beyond force generation.

scholarly journals Sec1p directly stimulates SNARE-mediated membrane fusion in vitro

2004 ◽  
Vol 167 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Brenton L. Scott ◽  
Jeffrey S. Van Komen ◽  
Hassan Irshad ◽  
Song Liu ◽  
Kirilee A. Wilson ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Fusion ◽  
Membrane Trafficking ◽  
Snare Complex ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Bud Neck ◽  
Precise Role

Sec1 proteins are critical players in membrane trafficking, yet their precise role remains unknown. We have examined the role of Sec1p in the regulation of post-Golgi secretion in Saccharomyces cerevisiae. Indirect immunofluorescence shows that endogenous Sec1p is found primarily at the bud neck in newly budded cells and in patches broadly distributed within the plasma membrane in unbudded cells. Recombinant Sec1p binds strongly to the t-SNARE complex (Sso1p/Sec9c) as well as to the fully assembled ternary SNARE complex (Sso1p/Sec9c;Snc2p), but also binds weakly to free Sso1p. We used recombinant Sec1p to test Sec1p function using a well-characterized SNARE-mediated membrane fusion assay. The addition of Sec1p to a traditional in vitro fusion assay moderately stimulates fusion; however, when Sec1p is allowed to bind to SNAREs before reconstitution, significantly more Sec1p binding is detected and fusion is stimulated in a concentration-dependent manner. These data strongly argue that Sec1p directly stimulates SNARE-mediated membrane fusion.

scholarly journals Fungal septins: one ring to rule it all?

2009 ◽  
Vol 4 (3) ◽  
pp. 274-289 ◽  
Author(s):  
Alberto González-Novo ◽  
Carlos Vázquez de Aldana ◽  
Javier Jiménez
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Hyphal Growth ◽  
Diffusion Barriers ◽  
Ashbya Gossypii ◽  
Molecular Architecture ◽  
Gtp Binding ◽  
Bud Neck ◽  
Living Organisms ◽  
Order Structures

AbstractSeptins are a conserved family of GTP-binding proteins found in living organisms ranging from yeasts to mammals. They are able to polymerize and form hetero-oligomers that assemble into higher-order structures whose detailed molecular architecture has recently been described in different organisms. In Saccharomyces cerevisiae, septins exert numerous functions throughout the cell cycle, serving as scaffolds for many different proteins or as diffusion barriers at the bud neck. In other fungi, septins are required for the proper completion of diverse functions such as polarized growth or pathogenesis. Recent results from several fungi have revealed important differences in septin organization and regulation as compared with S. cerevisiae, especially during Candida albicans hyphal growth and in Ashbya gossypii. Here we focus on these recent findings, their relevance in the biology of these eukaryotes and in consequence the “renaissance” of the study of septin structures in cells showing a different kind of morphological behaviour.

The role of DUBs in the post-translational control of cell migration

2019 ◽  
Vol 63 (5) ◽  
pp. 579-594 ◽  
Author(s):  
Guillem Lambies ◽  
Antonio García de Herreros ◽  
Víctor M. Díaz
Keyword(s):  
Cell Migration ◽  
Translational Control ◽  
Epithelial To Mesenchymal Transition ◽  
Extracellular Matrix Remodeling ◽  
Matrix Remodeling ◽  
Mesenchymal Transition ◽  
Tgfβ Receptors ◽  
Fundamental Process ◽  
Multistep Process

Abstract Cell migration is a multifactorial/multistep process that requires the concerted action of growth and transcriptional factors, motor proteins, extracellular matrix remodeling and proteases. In this review, we focus on the role of transcription factors modulating Epithelial-to-Mesenchymal Transition (EMT-TFs), a fundamental process supporting both physiological and pathological cell migration. These EMT-TFs (Snail1/2, Twist1/2 and Zeb1/2) are labile proteins which should be stabilized to initiate EMT and provide full migratory and invasive properties. We present here a family of enzymes, the deubiquitinases (DUBs) which have a crucial role in counteracting polyubiquitination and proteasomal degradation of EMT-TFs after their induction by TGFβ, inflammatory cytokines and hypoxia. We also describe the DUBs promoting the stabilization of Smads, TGFβ receptors and other key proteins involved in transduction pathways controlling EMT.

scholarly journals The Dynamic Interaction between Extracellular Matrix Remodeling and Breast Tumor Progression

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1046
Author(s):  
Jorge Martinez ◽  
Patricio C. Smith
Keyword(s):  
Extracellular Matrix ◽  
Type I Collagen ◽  
Cell Metabolism ◽  
Breast Tumors ◽  
Extracellular Matrix Remodeling ◽  
Type I ◽  
Matrix Remodeling ◽  
Desmoplastic Reaction ◽  
The Impact

Desmoplastic tumors correspond to a unique tissue structure characterized by the abnormal deposition of extracellular matrix. Breast tumors are a typical example of this type of lesion, a property that allows its palpation and early detection. Fibrillar type I collagen is a major component of tumor desmoplasia and its accumulation is causally linked to tumor cell survival and metastasis. For many years, the desmoplastic phenomenon was considered to be a reaction and response of the host tissue against tumor cells and, accordingly, designated as “desmoplastic reaction”. This notion has been challenged in the last decades when desmoplastic tissue was detected in breast tissue in the absence of tumor. This finding suggests that desmoplasia is a preexisting condition that stimulates the development of a malignant phenotype. With this perspective, in the present review, we analyze the role of extracellular matrix remodeling in the development of the desmoplastic response. Importantly, during the discussion, we also analyze the impact of obesity and cell metabolism as critical drivers of tissue remodeling during the development of desmoplasia. New knowledge derived from the dynamic remodeling of the extracellular matrix may lead to novel targets of interest for early diagnosis or therapy in the context of breast tumors.

scholarly journals Septin-dependent compartmentalization of the endoplasmic reticulum during yeast polarized growth

2005 ◽  
Vol 169 (6) ◽  
pp. 897-908 ◽  
Author(s):  
Cosima Luedeke ◽  
Stéphanie Buvelot Frei ◽  
Ivo Sbalzarini ◽  
Heinz Schwarz ◽  
Anne Spang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Diffusion Barriers ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Protein Diffusion ◽  
Ultrastructural Studies ◽  
Bud Neck ◽  
Er Membrane

Polarized cells frequently use diffusion barriers to separate plasma membrane domains. It is unknown whether diffusion barriers also compartmentalize intracellular organelles. We used photobleaching techniques to characterize protein diffusion in the yeast endoplasmic reticulum (ER). Although a soluble protein diffused rapidly throughout the ER lumen, diffusion of ER membrane proteins was restricted at the bud neck. Ultrastructural studies and fluorescence microscopy revealed the presence of a ring of smooth ER at the bud neck. This ER domain and the restriction of diffusion for ER membrane proteins through the bud neck depended on septin function. The membrane-associated protein Bud6 localized to the bud neck in a septin-dependent manner and was required to restrict the diffusion of ER membrane proteins. Our results indicate that Bud6 acts downstream of septins to assemble a fence in the ER membrane at the bud neck. Thus, in polarized yeast cells, diffusion barriers compartmentalize the ER and the plasma membrane along parallel lines.

scholarly journals Aryl Hydrocarbon Receptor Activation Impairs Extracellular Matrix Remodeling during Zebra Fish fin Regeneration

2006 ◽  
Vol 95 (1) ◽  
pp. 215-226 ◽  
Author(s):  
Eric A. Andreasen ◽  
Lijoy K. Mathew ◽  
Christiane V. Löhr ◽  
Rachelle Hasson ◽  
Robert L. Tanguay
Keyword(s):  
Extracellular Matrix ◽  
Aryl Hydrocarbon Receptor ◽  
Receptor Activation ◽  
Extracellular Matrix Remodeling ◽  
Matrix Remodeling ◽  
Zebra Fish ◽  
Fin Regeneration ◽  
Aryl Hydrocarbon
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