Browse
Submit Data
Databases
API
Help

Dataset Information

16 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Sequestration of the exocytic SNARE Psy1 into multiprotein nodes reinforces polarized morphogenesis in fission yeast.

ABSTRACT: Polarized morphogenesis is achieved by targeting or inhibiting growth in distinct regions. Rod-shaped fission yeast cells grow exclusively at their ends by restricting exocytosis and secretion to these sites. This growth pattern implies the existence of mechanisms that prevent exocytosis and growth along nongrowing cell sides. We previously identified a set of 50-100 megadalton-sized node structures along the sides of fission yeast cells that contained the interacting proteins Skb1 and Slf1. Here, we show that Skb1-Slf1 nodes contain the syntaxin-like soluble N-ethylmaleimide-sensitive factor attachment protein receptor Psy1, which mediates exocytosis in fission yeast. Psy1 localizes in a diffuse pattern at cell tips, where it likely promotes exocytosis and growth, but is sequestered in Skb1-Slf1 nodes at cell sides where growth does not occur. Mutations that prevent node assembly or inhibit Psy1 localization to nodes lead to aberrant exocytosis at cell sides and increased cell width. Genetic results indicate that this Psy1 node mechanism acts in parallel to actin cables and Cdc42 regulation. Our work suggests that sequestration of syntaxin-like Psy1 at nongrowing regions of the cell cortex reinforces cell morphology by restricting exocytosis to proper sites of polarized growth.

SUBMITTER: Miller KE

PROVIDER: S-EPMC8684755 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

TRIM67 regulates exocytic mode and neuronal morphogenesis via SNAP47.

Project description:Neuronal morphogenesis involves dramatic plasma membrane expansion, fueled by soluble N-ethylmaleimide-sensitive factor attachment protein eceptors (SNARE)-mediated exocytosis. Distinct fusion modes described at synapses include full-vesicle fusion (FVF) and kiss-and-run fusion (KNR). During FVF, lumenal cargo is secreted and vesicle membrane incorporates into the plasma membrane. During KNR, a transient fusion pore secretes cargo but closes without membrane addition. In contrast, fusion modes are not described in developing neurons. Here, we resolve individual exocytic events in developing murine cortical neurons and use classification tools to identify four distinguishable fusion modes: two FVF-like modes that insert membrane material and two KNR-like modes that do not. Discrete fluorescence profiles suggest distinct behavior of the fusion pore. Simulations and experiments agree that FVF-like exocytosis provides sufficient membrane material for morphogenesis. We find the E3 ubiquitin ligase TRIM67 promotes FVF-like exocytosis in part by limiting incorporation of the Qb/Qc SNARE SNAP47 into SNARE complexes and, thus, SNAP47 involvement in exocytosis.

| S-EPMC7941186 | biostudies-literature

GIV/Girdin and Exo70 Collaboratively Regulate the Mammalian Polarized Exocytic Machinery.

Project description:Polarized exocytosis is a fundamental process by which membranes and cargo proteins are delivered to the cell surface with precise spatial control. Although the need for the octameric exocyst complex is conserved from yeast to humans, what imparts spatial control is known only in yeast, i.e., a polarity scaffold called Bem1p. We demonstrate here that the mammalian scaffold protein, GIV/Girdin, fulfills the key criteria and functions of its yeast counterpart Bem1p; both bind Exo70 proteins via similar short-linear interaction motifs, and each prefers its evolutionary counterpart. Selective disruption of the GIV⋅Exo-70 interaction derails the delivery of the metalloprotease MT1-MMP to invadosomes and impairs collagen degradation and haptotaxis through basement membrane matrix. GIV's interacting partners reveal other components of polarized exocytosis in mammals. Findings expose how the exocytic functions aid GIV's pro-metastatic functions and how signal integration via GIV may represent an evolutionary advancement of the exocytic process in mammals.

| S-EPMC7322189 | biostudies-literature

Escherichia coli exposure inhibits exocytic SNARE-mediated membrane fusion in mast cells.

Project description:Mast cells orchestrate the allergic response through the release of proinflammatory mediators, which is driven by the fusion of cytoplasmic secretory granules with the plasma membrane. During this process, SNARE proteins including Syntaxin4, SNAP23 and VAMP8 play a key role. Following stimulation, the kinase IKK? interacts with and phosphorylates the t-SNARE SNAP23. Phosphorylated SNAP23 then associates with Syntaxin4 and the v-SNARE VAMP8 to form a ternary SNARE complex, which drives membrane fusion and mediator release. Interestingly, mast cell degranulation is impaired following exposure to bacteria such as Escherichia coli. However, the molecular mechanism(s) by which this occurs is unknown. Here, we show that E. coli exposure rapidly and additively inhibits degranulation in the RBL-2H3 rat mast cell line. Following co-culture with E. coli, the interaction between IKK? and SNAP23 is disrupted, resulting in the hypophosphorylation of SNAP23. Subsequent formation of the ternary SNARE complex between SNAP23, Syntaxin4 and VAMP8 is strongly reduced. Collectively, these results demonstrate that E. coli exposure inhibits the formation of VAMP8-containing exocytic SNARE complexes and thus the release of VAMP8-dependent granules by interfering with SNAP23 phosphorylation.

| S-EPMC4048993 | biostudies-literature

The SNARE VAMP7 Regulates Exocytic Trafficking of Interleukin-12 in Dendritic Cells.

Project description:Interleukin-12 (IL-12), produced by dendritic cells in response to activation, is central to pathogen eradication and tumor rejection. The trafficking pathways controlling spatial distribution and intracellular transport of IL-12 vesicles to the cell surface are still unknown. Here, we show that intracellular IL-12 localizes in late endocytic vesicles marked by the SNARE VAMP7. Dendritic cells (DCs) from VAMP7-deficient mice are partially impaired in the multidirectional release of IL-12. Upon encounter with antigen-specific T cells, IL-12-containing vesicles rapidly redistribute at the immune synapse and release IL-12 in a process entirely dependent on VAMP7 expression. Consistently, acquisition of effector functions is reduced in T cells stimulated by VAMP7-null DCs. These results provide insights into IL-12 intracellular trafficking pathways and show that VAMP7-mediated release of IL-12 at the immune synapse is a mechanism to transmit innate signals to T cells.

| S-EPMC4806224 | biostudies-literature

Meiosis-specific localization of the exocytic Rab Ypt2 in fission yeast.

Project description:Fission yeast Ypt2, an orthologue of the mammalian small GTPase Rab8, is responsible for post-Golgi membrane trafficking. During meiosis, Ypt2 localizes at the spindle pole body (SPB), where it regulates de novo biogenesis of the spore plasma membrane. Recruitment of Ypt2 to the SPB is dependent on its meiosis-specific GDP/GTP exchange factor (GEF), the SPB-resident protein Spo13. Here we have examined the SPB recruitment of Ypt2 by Spo13. The GEF activity of Spo13 was required, but not essential for recruitment. Furthermore, Ypt2 recruitment was regulated in a meiosis-specific manner and partially regulated by the nuclear Dbf2-related (NDR) kinase Sid2, indicating the existence of a novel regulatory mechanism for localization of Rab GTPases during meiosis.

| S-EPMC7204522 | biostudies-literature

COPI mediates recycling of an exocytic SNARE by recognition of a ubiquitin sorting signal.

Project description:The COPI coat forms transport vesicles from the Golgi complex and plays a poorly defined role in endocytic trafficking. Here we show that COPI binds K63-linked polyubiquitin and this interaction is crucial for trafficking of a ubiquitinated yeast SNARE (Snc1). Snc1 is a v-SNARE that drives fusion of exocytic vesicles with the plasma membrane, and then recycles through the endocytic pathway to the Golgi for reuse in exocytosis. Removal of ubiquitin from Snc1, or deletion of a ?'-COP subunit propeller domain that binds K63-linked polyubiquitin, disrupts Snc1 recycling causing aberrant accumulation in internal compartments. Moreover, replacement of the ?'-COP propeller domain with unrelated ubiquitin-binding domains restores Snc1 recycling. These results indicate that ubiquitination, a modification well known to target membrane proteins to the lysosome or vacuole for degradation, can also function as recycling signal to sort a SNARE into COPI vesicles in a non-degradative pathway.

| S-EPMC5663479 | biostudies-literature

Single SNARE-mediated vesicle fusion observed in vitro by polarized TIRFM.

Project description:Single-vesicle fusion assays in vitro are useful tools for examining mechanisms of membrane fusion at the molecular level mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). This approach allows the experimentalist to define the lipid and protein composition of the two fusing membranes and perform experiments under highly controlled conditions. In previous experiments, in which we reconstituted a SNARE acceptor complex into supported membranes and observed the docking and fusion of fluorescently labeled synaptobrevin proteoliposomes by total internal reflection fluorescence microscopy with millisecond time resolution, we were able to determine the optimal number of SNARE complexes needed for fast fusion. Here, we utilize this assay in combination with polarized total internal reflection fluorescence microscopy to investigate topology changes that vesicles undergo after the onset of fusion. The theory that describes the fluorescence intensity during the transformation of a single vesicle from a spherical particle to a flat membrane patch is developed and confirmed by experiments with three different fluorescent probes. Our results show that on average, the fusing vesicles flatten and merge into the planar membrane within 8 ms after fusion starts.

| S-EPMC3000493 | biostudies-literature

Dual modes of cdc42 recycling fine-tune polarized morphogenesis.

Project description:In budding yeast, the highly conserved small GTPase Cdc42 localizes to the cortex at a cell pole and orchestrates the trafficking and deposition of cell surface materials required for building a bud or mating projection (shmoo). Using a combination of quantitative imaging and mathematical modeling, we elucidate mechanisms of dynamic recycling of Cdc42 that balance diffusion. Rdi1, a guanine nucleotide dissociation inhibitor (GDI), mediates a fast recycling pathway, while actin patch-mediated endocytosis accounts for a slower one. These recycling mechanisms are restricted to the same region of the nascent bud, as both are coupled to the Cdc42 GTPase cycle. We find that a single dynamic parameter, the rate of internalization inside the window of polarized delivery, is tuned to give rise to distinct shapes of Cdc42 distributions that correlate with distinct morphogenetic fates, such as the formation of a round bud or a pointed shmoo.

| S-EPMC2805562 | biostudies-literature

Compartmentalized nodes control mitotic entry signaling in fission yeast.

Project description:Cell cycle progression is coupled to cell growth, but the mechanisms that generate growth-dependent cell cycle progression remain unclear. Fission yeast cells enter into mitosis at a defined size due to the conserved cell cycle kinases Cdr1 and Cdr2, which localize to a set of cortical nodes in the cell middle. Cdr2 is regulated by the cell polarity kinase Pom1, suggesting that interactions between cell polarity proteins and the Cdr1-Cdr2 module might underlie the coordination of cell growth and division. To identify the molecular connections between Cdr1/2 and cell polarity, we performed a comprehensive pairwise yeast two-hybrid screen. From the resulting interaction network, we found that the protein Skb1 interacted with both Cdr1 and the Cdr1 inhibitory target Wee1. Skb1 inhibited mitotic entry through negative regulation of Cdr1 and localized to both the cytoplasm and a novel set of cortical nodes. Skb1 nodes were distinct structures from Cdr1/2 nodes, and artificial targeting of Skb1 to Cdr1/2 nodes delayed entry into mitosis. We propose that the formation of distinct node structures in the cell cortex controls signaling pathways to link cell growth and division.

| S-EPMC3681693 | biostudies-literature

AFR1 promotes polarized apical morphogenesis in Saccharomyces cerevisiae.

Project description:The G protein-coupled alpha-factor receptor promotes polarized growth toward a mating partner. alpha-Factor induces the expression of AFR1, which acts together with the receptor C terminus to promote normal morphogenesis. The function of AFR1 was investigated by engineering cells to constitutively express AFR1 without alpha-factor. Constitutive AFR1 expression caused cells to form elongated buds that demonstrate that AFR1 can also interact with the morphogenesis components that promote bud formation. A similar elongated bud phenotype is caused by mutation of the CDC3, CDC10, CDC11, and CDC12 genes, which encode putative filament proteins that form a ring at the bud neck. AFR1 may act directly on the filament proteins, since immunolocalization detected AFR1 at the bud neck and interaction of AFR1 and CDC12 was detected in the two-hybrid protein assay. AFR1 localized to the base of pheromone-induced projections. These results suggest that AFR1 and the putative filament proteins act together with the receptor to facilitate proper localization of components during mating.

| S-EPMC231939 | biostudies-other

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data