ORP-Mediated ER Contact with Endocytic Sites Facilitates Actin Polymerization

Dedo, Javier Encinar del; Idrissi, Fátima-Zahra; Fernández-Golbano, Isabel María; Garcia, Patrícia Salomão; Rebollo, Elena; Krzyzanowski, Marek K.; Geli, Maribel

doi:10.1016/j.devcel.2017.10.031

Cited by 44 publications

(49 citation statements)

References 67 publications

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“…The kinase Ppk25 does not have extensive regulatory domains, but its kinase domain is most similar to that of the budding yeast paralogs Kin1 and Kin2, which function in late stages of exocytosis through phosphorylation of t-SNARE Sec9 ( Elbert et al., 2005 ). Budding yeast Osh2, a member of a conserved family of oxysterol-binding protein-related proteins ( Raychaudhuri and Prinz, 2010 ), facilitates endocytosis at plasma membrane regions that contact cortical endoplasmic reticulum ( Encinar Del Dedo et al., 2017 ). Collectively, the functions of these proteins in budding yeast suggest that in fission yeast, Orb6 coordinates multiple processes related to membrane trafficking.…”

Section: Discussionmentioning

confidence: 99%

Fission Yeast NDR/LATS Kinase Orb6 Regulates Exocytosis via Phosphorylation of the Exocyst Complex

et al. 2019

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SummaryNDR/LATS kinases regulate multiple aspects of cell polarity and morphogenesis from yeast to mammals. Fission yeast NDR/LATS kinase Orb6 has been proposed to control cell polarity by regulating the Cdc42 guanine nucleotide exchange factor Gef1. Here, we show that Orb6 regulates polarity largely independently of Gef1 and that Orb6 positively regulates exocytosis. Through Orb6 inhibition in vivo and quantitative global phosphoproteomics, we identify Orb6 targets, including proteins involved in membrane trafficking. We confirm Sec3 and Sec5, conserved components of the exocyst complex, as substrates of Orb6 both in vivo and in vitro, and we show that Orb6 kinase activity is important for exocyst localization to cell tips and for exocyst activity during septum dissolution after cytokinesis. We further find that Orb6 phosphorylation of Sec3 contributes to exocyst function in concert with exocyst protein Exo70. We propose that Orb6 contributes to polarized growth by regulating membrane trafficking at multiple levels.

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Section: Discussionmentioning

confidence: 99%

Fission Yeast NDR/LATS Kinase Orb6 Regulates Exocytosis via Phosphorylation of the Exocyst Complex

et al. 2019

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“…5C and Video 6). Because of described links of Osh2 and Osh3 with Arp2/3 activation in S. cerevisiae(Encinar Del Dedo et al, 2017), we also…”

mentioning

confidence: 99%

Sterol biosensor reveals LAM-family Ltc1-dependent sterol flow to endosomes upon Arp2/3 inhibition

Marek

Vincenzetti

2020

Journal of Cell Biology

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Sterols are crucial components of biological membranes, which are synthetized in the ER and accumulate in the plasma membrane (PM). Here, by applying a genetically encoded sterol biosensor (D4H), we visualize a sterol flow between PM and endosomes in the fission yeast Schizosaccharomyces pombe. Using time-lapse and correlative light-electron microscopy, we found that inhibition of Arp2/3-dependent F-actin assembly promotes the reversible relocalization of D4H from the PM to internal sterol-rich compartments (STRIC) labeled by synaptobrevin Syb1. Retrograde sterol internalization to STRIC is independent of endocytosis or an intact Golgi, but depends on Ltc1, a LAM/StARkin-family protein localized to ER-PM contact sites. The PM in ltc1Δ cells over-accumulates sterols and upon Arp2/3 inhibition forms extended ER-interacting invaginations, indicating that sterol transfer contributes to PM size homeostasis. Anterograde sterol movement from STRIC is independent of canonical vesicular trafficking but requires Arp2/3, suggesting a novel role for this complex. Thus, transfer routes orthogonal to vesicular trafficking govern the flow of sterols in the cell.

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“…A recent paper reported transient interactions between Osh2p and nascent endocytic sites on the PM near associated “cER rims” ( Encinar del Dedo et al, 2017 ). Through interactions with the type I myosin Myo5p and Scs2p, it is proposed that Osh2p regulates cER-endocytic site associations to facilitate actin patch assembly for endocytic internalization ( Encinar del Dedo et al, 2017 ). These studies raise the possibility that Osh2p and Scs2p couple Myo5p-dependent actin polymerization with the clearance of cER from endocytic sites undergoing membrane invagination.…”

Section: Er-pm Tethers In Budding Yeast Are Mechanistically Varied Anmentioning

confidence: 99%

Sticking With It: ER-PM Membrane Contact Sites as a Coordinating Nexus for Regulating Lipids and Proteins at the Cell Cortex

Zaman

Nenadic

Radojičić

et al. 2020

Front. Cell Dev. Biol.

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Membrane contact sites between the cortical endoplasmic reticulum (ER) and the plasma membrane (PM) provide a direct conduit for small molecule transfer and signaling between the two largest membranes of the cell. Contact is established through ER integral membrane proteins that physically tether the two membranes together, though the general mechanism is remarkably non-specific given the diversity of different tethering proteins. Primary tethers including VAMP-associated proteins (VAPs), Anoctamin/TMEM16/Ist2p homologs, and extended synaptotagmins (E-Syts), are largely conserved in most eukaryotes and are both necessary and sufficient for establishing ER-PM association. In addition, other species-specific ER-PM tether proteins impart unique functional attributes to both membranes at the cell cortex. This review distils recent functional and structural findings about conserved and speciesspecific tethers that form ER-PM contact sites, with an emphasis on their roles in the coordinate regulation of lipid metabolism, cellular structure, and responses to membrane stress.

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ORP-Mediated ER Contact with Endocytic Sites Facilitates Actin Polymerization

Cited by 44 publications

References 67 publications

Fission Yeast NDR/LATS Kinase Orb6 Regulates Exocytosis via Phosphorylation of the Exocyst Complex

Fission Yeast NDR/LATS Kinase Orb6 Regulates Exocytosis via Phosphorylation of the Exocyst Complex

Sterol biosensor reveals LAM-family Ltc1-dependent sterol flow to endosomes upon Arp2/3 inhibition

Sticking With It: ER-PM Membrane Contact Sites as a Coordinating Nexus for Regulating Lipids and Proteins at the Cell Cortex

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