scholarly journals Plasma Membrane Localization Is Essential for Oryza sativa Pto-Interacting Protein 1a-Mediated Negative Regulation of Immune Signaling in Rice

2014 ◽  
Vol 166 (1) ◽  
pp. 327-336 ◽  
Author(s):  
Hidenori Matsui ◽  
Masayuki Fujiwara ◽  
Satoshi Hamada ◽  
Ko Shimamoto ◽  
Yuko Nomura ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Plasma Membrane ◽  
Negative Regulation ◽  
Membrane Localization ◽  
Immune Signaling ◽  
Interacting Protein ◽  
Plasma Membrane Localization

scholarly journals Munc18-1 Is Critical for Plasma Membrane Localization of Syntaxin1 but Not of SNAP-25 in PC12 Cells

2008 ◽  
Vol 19 (2) ◽  
pp. 722-734 ◽  
Author(s):  
Lakshmanan Arunachalam ◽  
Liping Han ◽  
Nardos G. Tassew ◽  
Yu He ◽  
Li Wang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Critical Role ◽  
Neuroendocrine Cells ◽  
Dense Core ◽  
Expression Level ◽  
Membrane Localization ◽  
Dense Core Vesicles ◽  
Interacting Protein ◽  
Plasma Membrane Localization ◽  
Mutant Phenotypes

Although Munc18-1 was originally identified as a syntaxin1–interacting protein, the physiological significance of this interaction remains unclear. In fact, recent studies of Munc18-1 mutants have suggested that Munc18-1 plays a critical role for docking of secretory vesicles, independent of syntaxin1 regulation. Here we investigated the role of Munc18-1 in syntaxin1 localization by generating stable neuroendocrine cell lines in which Munc18-1 was strongly down-regulated. In these cells, the secretion capability, as well as the docking of dense-core vesicles, was significantly reduced. More importantly, not only was the expression level of syntaxin1 reduced, but the localization of syntaxin1 at the plasma membrane was also severely perturbed. The mislocalized syntaxin1 resided primarily in the perinuclear region of the cells, in which it was highly colocalized with Secretogranin II, a marker protein for dense-core vesicles. In contrast, the expression level and the plasma membrane localization of SNAP-25 were not affected. Furthermore, the syntaxin1 localization and the secretion capability were restored upon transfection-mediated reintroduction of Munc18-1. Our results indicate that endogenous Munc18-1 plays a critical role for the plasma membrane localization of syntaxin1 in neuroendocrine cells and therefore necessitates the interpretation of Munc18-1 mutant phenotypes to be in terms of mislocalized syntaxin1.

scholarly journals Lipid binding by the N-terminal motif mediates plasma membrane localization of Bordetella effector protein BteA

2021 ◽  
pp. 100607
Author(s):  
Ivana Malcova ◽  
Ladislav Bumba ◽  
Filip Uljanic ◽  
Darya Kuzmenko ◽  
Jana Nedomova ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lipid Binding ◽  
Membrane Localization ◽  
Effector Protein ◽  
Plasma Membrane Localization

scholarly journals Palmitoylation of Sindbis Virus TF Protein Regulates Its Plasma Membrane Localization and Subsequent Incorporation into Virions

2016 ◽  
Vol 91 (3) ◽  
Author(s):  
Jolene Ramsey ◽  
Emily C. Renzi ◽  
Randy J. Arnold ◽  
Jonathan C. Trinidad ◽  
Suchetana Mukhopadhyay
Keyword(s):  
Plasma Membrane ◽  
Sindbis Virus ◽  
Molecular Mechanisms ◽  
Wild Type Virus ◽  
Membrane Localization ◽  
Clear Understanding ◽  
Wild Type ◽  
Plasma Membrane Localization ◽  
C Terminus ◽  
N Terminus

ABSTRACT Palmitoylation is a reversible, posttranslational modification that helps target proteins to cellular membranes. The alphavirus small membrane proteins 6K and TF have been reported to be palmitoylated and to positively regulate budding. 6K and TF are isoforms that are identical in their N termini but unique in their C termini due to a −1 ribosomal frameshift during translation. In this study, we used cysteine (Cys) mutants to test differential palmitoylation of the Sindbis virus 6K and TF proteins. We modularly mutated the five Cys residues in the identical N termini of 6K and TF, the four additional Cys residues in TF's unique C terminus, or all nine Cys residues in TF. Using these mutants, we determined that TF palmitoylation occurs primarily in the N terminus. In contrast, 6K is not palmitoylated, even on these shared residues. In the C-terminal Cys mutant, TF protein levels increase both in the cell and in the released virion compared to the wild type. In viruses with the N-terminal Cys residues mutated, TF is much less efficiently localized to the plasma membrane, and it is not incorporated into the virion. The three Cys mutants have minor defects in cell culture growth but a high incidence of abnormal particle morphologies compared to the wild-type virus as determined by transmission electron microscopy. We propose a model where the C terminus of TF modulates the palmitoylation of TF at the N terminus, and palmitoylated TF is preferentially trafficked to the plasma membrane for virus budding. IMPORTANCE Alphaviruses are a reemerging viral cause of arthritogenic disease. Recently, the small 6K and TF proteins of alphaviruses were shown to contribute to virulence in vivo. Nevertheless, a clear understanding of the molecular mechanisms by which either protein acts to promote virus infection is missing. The TF protein is a component of budded virions, and optimal levels of TF correlate positively with wild-type-like particle morphology. In this study, we show that the palmitoylation of TF regulates its localization to the plasma membrane, which is the site of alphavirus budding. Mutants in which TF is not palmitoylated display drastically reduced plasma membrane localization, which effectively prevents TF from participating in budding or being incorporated into virus particles. Investigation of the regulation of TF will aid current efforts in the alphavirus field searching for approaches to mitigate alphaviral disease in humans.

scholarly journals A novel RCE1 isoform is required for H-Ras plasma membrane localization and is regulated by USP17

2013 ◽  
Vol 457 (2) ◽  
pp. 289-300 ◽  
Author(s):  
Jakub Jaworski ◽  
Ureshnie Govender ◽  
Cheryl McFarlane ◽  
Michelle de la Vega ◽  
Michelle K. Greene ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Localization ◽  
Plasma Membrane Localization

We have identified a novel RCE1 isoform which is required for proper H-Ras processing and plasma membrane localization. In addition, we have shown that USP17 can regulate this novel isoform and thus RCE1 activity by deubiquitinating Lys43.

scholarly journals Role of Ezrin/Radixin/Moesin in the Surface Localization of Programmed Cell Death Ligand-1 in Human Colon Adenocarcinoma LS180 Cells

2021 ◽  
Vol 14 (9) ◽  
pp. 864
Author(s):  
Takuro Kobori ◽  
Chihiro Tanaka ◽  
Mayuka Tameishi ◽  
Yoko Urashima ◽  
Takuya Ito ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Programmed Cell Death ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Mrna Level ◽  
Scaffold Proteins ◽  
Membrane Localization ◽  
Erm Proteins ◽  
Plasma Membrane Localization

Programmed cell death ligand-1 (PD-L1), an immune checkpoint protein highly expressed on the cell surface in various cancer cell types, binds to programmed cell death-1 (PD-1), leading to T-cell dysfunction and tumor survival. Despite clinical successes of PD-1/PD-L1 blockade therapies, patients with colorectal cancer (CRC) receive little benefit because most cases respond poorly. Because high PD-L1 expression is associated with immune evasion and poor prognosis in CRC patients, identifying potential modulators for the plasma membrane localization of PD-L1 may represent a novel therapeutic strategy for enhancing the efficacy of PD-1/PD-L1 blockade therapies. Here, we investigated whether PD-L1 expression in human colorectal adenocarcinoma cells (LS180) is affected by ezrin/radixin/moesin (ERM), functioning as scaffold proteins that crosslink plasma membrane proteins with the actin cytoskeleton. We observed colocalization of PD-L1 with all three ERM proteins in the plasma membrane and detected interactions involving PD-L1, the three ERM proteins, and the actin cytoskeleton. Furthermore, gene silencing of ezrin and radixin, but not of moesin, substantially decreased the expression of PD-L1 on the cell surface without affecting its mRNA level. Thus, in LS180 cells, ezrin and radixin may function as scaffold proteins mediating the plasma membrane localization of PD-L1, possibly by post-translational modification.

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