Spatiotemporal control of phosphatidylinositol 4-phosphate by Sac2 regulates endocytic recycling
Ontology highlight
ABSTRACT:
SUBMITTER: FoSheng Hsu
PROVIDER: S-JCBD-201408027 | bioimages |
REPOSITORIES: bioimages
Similar Datasets
Project description:It is well established that the spatial- and temporal-restricted generation and turnover of phosphoinositides (PIs) by a cascade of PI-metabolizing enzymes is a key regulatory mechanism in the endocytic pathway. Here, we demonstrate that the Sac1 domain-containing protein Sac2 is a PI 4-phosphatase that specifically hydrolyzes phosphatidylinositol 4-phosphate in vitro. We further show that Sac2 colocalizes with early endosomal markers and is recruited to transferrin (Tfn)-containing vesicles during endocytic recycling. Exogenous expression of the catalytically inactive mutant Sac2C458S resulted in altered cellular distribution of Tfn receptors and delayed Tfn recycling. Furthermore, genomic ablation of Sac2 caused a similar perturbation on Tfn and integrin recycling as well as defects in cell migration. Structural characterization of Sac2 revealed a unique pleckstrin-like homology Sac2 domain conserved in all Sac2 orthologues. Collectively, our findings provide evidence for the tight regulation of PIs by Sac2 in the endocytic recycling pathway.
| S-EPMC4395482 | biostudies-literature
Project description:A balance between endocytosis and membrane recycling regulates the composition and dynamics of the plasma membrane. Internalization and recycling of cholesterol- and sphingolipid-enriched lipid rafts is an actin-dependent process that is mediated by a specialized Arf6-dependent recycling pathway. Here, we identify myosin1c (Myo1c) as the first motor protein that drives the formation of recycling tubules emanating from the perinuclear recycling compartment. We demonstrate that the single-headed Myo1c is a lipid-raft-associated motor protein that is specifically involved in recycling of lipid-raft-associated glycosylphosphatidylinositol (GPI)-linked cargo proteins and their delivery to the cell surface. Whereas Myo1c overexpression increases the levels of these raft proteins at the cell surface, in cells depleted of Myo1c function through RNA interference or overexpression of a dominant-negative mutant, these tubular transport carriers of the recycling pathway are lost and GPI-linked raft markers are trapped in the perinuclear recycling compartment. Intriguingly, Myo1c only selectively promotes delivery of lipid raft membranes back to the cell surface and is not required for recycling of cargo, such as the transferrin receptor, which is mediated by parallel pathways. The profound defect in lipid raft trafficking in Myo1c-knockdown cells has a dramatic impact on cell spreading, cell migration and cholesterol-dependent Salmonella invasion; processes that require lipid raft transport to the cell surface to deliver signaling components and the extra membrane essential for cell surface expansion and remodeling. Thus, Myo1c plays a crucial role in the recycling of lipid raft membrane and proteins that regulate plasma membrane plasticity, cell motility and pathogen entry.
| S-EPMC3360920 | biostudies-literature
Project description:Second messengers control a wide range of important cellular functions in eukaryotes and prokaryotes. Here we show that cyclic di-GMP, a global bacterial second messenger, promotes cell cycle progression in Caulobacter crescentus by mediating the specific degradation of the replication initiation inhibitor CtrA. During the G1-to-S-phase transition, both CtrA and its cognate protease ClpXP dynamically localize to the old cell pole, where CtrA is rapidly degraded. Sequestration of CtrA to the cell pole depends on PopA, a newly identified cyclic di-GMP effector protein. PopA itself localizes to the cell pole and directs CtrA to this subcellular site via the direct interaction with a mediator protein, RcdA. We present evidence that c-di-GMP regulates CtrA degradation during the cell cycle by controlling the dynamic sequestration of the PopA recruitment factor to the cell pole. Furthermore, we show that cell cycle timing of CtrA degradation relies on converging pathways responsible for substrate and protease localization to the old cell pole. This is the first report that links cyclic di-GMP to protein dynamics and cell cycle control in bacteria.
| S-EPMC2632171 | biostudies-literature
Project description:Intracellular recycling pathways play critical roles in internalizing membrane and fluid phase cargo and in balancing the inflow and outflow of membrane and cell surface molecules. To identify proteins involved in the regulation of endocytic recycling, we used an shRNA trafficking library and screened for changes in the surface expression of CD1a antigen-presenting molecules that follow an endocytic recycling route. We found that silencing of the ADP-ribosylation factor (Arf)-like small GTPase Arl13b led to a decrease in CD1a surface expression, diminished CD1a function, and delayed CD1a recycling, suggesting that Arl13b is involved in the regulation of endocytic recycling traffic. Arl13b appears to be required for the major route of endocytic trafficking, causing clustering of early endosomes and leading to the accumulation of endocytic cargo. Moreover, Arl13b colocalized with markers of the endocytic recycling pathway followed by CD1a, namely Arf6 and Rab22a. We also detected an interaction between Arl13b and the actin cytoskeleton. Arl13b was previously implicated in cilia formation and function. Our present results indicate a previously unidentified role for Arl13b in endocytic recycling traffic and suggest a link between Arl13b function and the actin cytoskeleton.
| S-EPMC3535586 | biostudies-literature
Project description:Endocytic recycling of receptors and lipids occurs via a complex network of tubular and vesicular membranes. EHD1 is a key regulator of endocytosis and associates with tubular membranes to facilitate recycling. Although EHD proteins tubulate membranes in vitro, EHD1 primarily associates with preexisting tubules in vivo. How EHD1 is recruited to these tubular endosomes remains unclear. We have determined that the Rab8-interacting protein, MICAL-L1, associates with EHD1, with both proteins colocalizing to long tubular membranes, in vitro and in live cells. MICAL-L1 is a largely uncharacterized member of the MICAL-family of proteins that uniquely contains two asparagine-proline-phenylalanine motifs, sequences that typically interact with EH-domains. Our data show that the MICAL-L1 C-terminal coiled-coil region is necessary and sufficient for its localization to tubular membranes. Moreover, we provide unexpected evidence that endogenous MICAL-L1 can link both EHD1 and Rab8a to these structures, as its depletion leads to loss of the EHD1-Rab8a interaction and the absence of both of these proteins from the membrane tubules. Finally, we demonstrate that MICAL-L1 is essential for efficient endocytic recycling. These data implicate MICAL-L1 as an unusual type of Rab effector that regulates endocytic recycling by recruiting and linking EHD1 and Rab8a on membrane tubules.
| S-EPMC2793294 | biostudies-literature
Project description:Rab8 is a monomeric GTPase that regulates the delivery of newly synthesized proteins to the basolateral surface in polarized epithelial cells. Recent publications have demonstrated that basolateral proteins interacting with the mu1-B clathrin adapter subunit pass through the recycling endosome (RE) en route from the TGN to the plasma membrane. Because Rab8 interacts with these basolateral proteins, these findings raise the question of whether Rab8 acts before, at, or after the RE. We find that Rab8 overexpression during the formation of polarity in MDCK cells, disrupts polarization of the cell, explaining how Rab8 mutants can disrupt basolateral endocytic and secretory traffic. However, once cells are polarized, Rab8 mutants cause mis-sorting of newly synthesized basolateral proteins such as VSV-G to the apical surface, but do not cause mis-sorting of membrane proteins already at the cell surface or in the endocytic recycling pathway. Enzymatic ablation of the RE also prevents traffic from the TGN from reaching the RE and similarly results in mis-sorting of newly synthesized VSV-G. We conclude that Rab8 regulates biosynthetic traffic through REs to the plasma membrane, but not trafficking of endocytic cargo through the RE. The data are consistent with a model in which Rab8 functions in regulating the delivery of TGN-derived cargo to REs.
| S-EPMC2366880 | biostudies-literature
Project description:The most general investigation and exploitation of light-induced processes require simultaneous control over spatial and temporal properties of the electromagnetic field on a femtosecond time and nanometer length scale. Based on the combination of polarization pulse shaping and time-resolved two-photon photoemission electron microscopy, we demonstrate such control over nanoscale spatial and ultrafast temporal degrees of freedom of an electromagnetic excitation in the vicinity of a nanostructure. The time-resolved cross-correlation measurement of the local photoemission yield reveals the switching of the nanolocalized optical near-field distribution with a lateral resolution well below the diffraction limit and a temporal resolution on the femtosecond time scale. In addition, successful adaptive spatiotemporal control demonstrates the flexibility of the method. This flexible simultaneous control of temporal and spatial properties of nanophotonic excitations opens new possibilities to tailor and optimize the light-matter interaction in spectroscopic methods as well as in nanophotonic applications.
| S-EPMC2851794 | biostudies-literature
Project description:Rab11 family-interacting protein 5 (Rab11fip5) is an adaptor protein that binds to the small GTPase Rab11, which has an important function in endosome recycling and trafficking of cellular proteins to the plasma membrane. Rab11fip5 is involved in many cellular processes, such as cytoskeleton rearrangement, iron uptake and exocytosis in neuroendocrine cells, and is also known as a candidate gene for autism-spectrum disorder. However, the role of Rab11fip5 during early embryonic development is not clearly understood. In this study, we identified Rab11fip5 as a protein that interacts with ephrinB1, a transmembrane ligand for Eph receptors. The PDZ binding motif in ephrinB1 and the Rab-binding domain in Rab11fip5 are necessary for their interaction in a complex. EphrinB1 and Rab11fip5 display overlapping expression in the telencephalon of developing amphibian embryos. The loss of Rab11fip5 function causes a reduction in telencephalon size and a decrease in the expression level of ephrinB1. Moreover, morpholino oligonucleotide-mediated knockdown of Rab11fip5 decreases cell proliferation in the telencephalon. The overexpression of ephrinB1 rescues these defects, suggesting that ephrinB1 recycling by the Rab11/Rab11fip5 complex is crucial for proper telencephalon development.
| S-EPMC7875491 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-03-14 | E-GEOD-46985 | biostudies-arrayexpress
Project description:Major histocompatibility complex class I (MHC I) presents intracellular-derived peptides to cytotoxic T lymphocytes and its subcellular itinerary is important in regulating the immune response. While a number of diacylglycerol kinase isoforms have been implicated in clathrin-dependent internalization, MHC I lacks the typical motifs known to mediate clathrin-dependent endocytosis. Here we show that depletion of diacylglycerol kinase α (DGKα), a kinase devoid of a clathrin-dependent adaptor protein complex 2 binding site, caused a delay in MHC I recycling to the plasma membrane without affecting the rate of MHC I internalization. We demonstrate that DGKα knock-down causes accumulation of intracellular and surface MHC I, resulting from decreased degradation. Furthermore, we provide evidence that DGKα is required for the generation of phosphatidic acid required for tubular recycling endosome (TRE) biogenesis. Moreover, we show that DGKα forms a complex with the TRE hub protein, MICAL-L1. Given that MICAL-L1 and the F-BAR-containing membrane-tubulating protein Syndapin2 associate selectively with phosphatidic acid, we propose a positive feedback loop in which DGKα generates phosphatidic acid to drive its own recruitment to TRE via its interaction with MICAL-L1. Our data support a novel role for the involvement of DGKα in TRE biogenesis and MHC I recycling.
| S-EPMC4231670 | biostudies-literature