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A human genome-wide screen for regulators of clathrin-coated vesicle formation

ABSTRACT: Clathrin-mediated endocytosis is essential for a wide range of cellular functions. We used a multi- step siRNA-based screening strategy to identify novel regulators of the first step of clathrin- mediated endocytosis, formation of clathrin-coated vesicles (CCVs) at the plasma membrane. A primary genome-wide screen identified 334 hits that caused accumulation of CCV cargo on the cell surface. A secondary screen identified 92 hits that inhibited cargo uptake and/or altered the morphology of clathrin-coated structures. The hits include components of four functional complexes: coat proteins, V-ATPase subunits, spliceosome-associated proteins, and acetyltransferase subunits. Electron microscopy revealed that V-ATPase depletion caused the cell to form aberrant non-constricted clathrin-coated structures at the plasma membrane. The V- ATPase knockdown phenotype was rescued by addition of exogenous cholesterol, indicating that the knockdown blocks clathrin-mediated endocytosis by preventing cholesterol from recycling from endosomes back to the plasma membrane. The microarray analysis was performed to test whether the siRNA targets are expressed in the cell lines used in the screen.

ORGANISM(S): Homo sapiens

PROVIDER: GSE39954 | GEO | 2012/12/01

SECONDARY ACCESSION(S): PRJNA172162

REPOSITORIES: GEO

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A human genome-wide screen for regulators of clathrin-coated vesicle formation

Project description:Clathrin-mediated endocytosis is essential for a wide range of cellular functions. We used a multi- step siRNA-based screening strategy to identify novel regulators of the first step of clathrin- mediated endocytosis, formation of clathrin-coated vesicles (CCVs) at the plasma membrane. A primary genome-wide screen identified 334 hits that caused accumulation of CCV cargo on the cell surface. A secondary screen identified 92 hits that inhibited cargo uptake and/or altered the morphology of clathrin-coated structures. The hits include components of four functional complexes: coat proteins, V-ATPase subunits, spliceosome-associated proteins, and acetyltransferase subunits. Electron microscopy revealed that V-ATPase depletion caused the cell to form aberrant non-constricted clathrin-coated structures at the plasma membrane. The V- ATPase knockdown phenotype was rescued by addition of exogenous cholesterol, indicating that the knockdown blocks clathrin-mediated endocytosis by preventing cholesterol from recycling from endosomes back to the plasma membrane. The microarray analysis was performed to test whether the siRNA targets are expressed in the cell lines used in the screen. For the microarray analysis of gene expression, the two cell lines used in the study were analyzed in duplicate: HeLa-YXXÎ¦ and HeLa-FXNPXY (Hela-M cells expressing a CD8-YXXÎ¦ and CD8-FXNPXY constructs respectively). YXXÎ¦ and FXNPXY are motifs for clathrin-mediated endocytosis.

2012-12-01 | E-GEOD-39954 | biostudies-arrayexpress

The endocytic TPLATE complex internalizes ubiquitinated plasma membrane cargo

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2023-03-11 | PXD035444 | Pride

Inositol triphosphate-triggered calcium release blocks lipid exchange at endoplasmic reticulum-Golgi contact sites

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Peturbation of PICALM Levels Alters Cellular Cholesterol Metabolism

Project description:PICALM (Phosphatidyl Inositol Clathrin Assembly Lymphoid Myeloid protein) is a ubiquitously expressed protein that plays a role in clathrin-mediated endocytosis. PICALM also affects the internalization of SNAREs and modulates macroautophagy. Chromosomal translocations that result in the fusion of PICALM to heterologous proteins cause leukemias, and genome-wide association studies have linked Single Nucleotide Polymorphisms (SNPs) of PICALM to Alzheimer’s disease. To obtain insight into the biological role of PICALM, we performed gene expression studies of PICALM-deficient and PICALM-expressing cells. Pathway analysis demonstrated that PICALM expression influences the expression of genes that encode proteins involved in cholesterol biosynthesis and lipoprotein uptake. GC-MS studies indicated that loss of PICALM increases total cholesterol pool size. Isotopic labeling studies revealed that loss of PICALM alters cholesterol homeostasis via increased scavenging of cholesterol. Measurement of LDL receptor endocytosis further showed that PICALM deficient cells express higher LDLR levels resulting in higher lipoprotein internalization. These findings suggest that PICALM is required for cellular cholesterol homeostasis and point to a novel mechanism by which PICALM alterations may contribute to disease. Total RNA was isolated (Qiagen RNeasy® Micro kit, Valencia, CA) from four replicates of PICALM knockout cells transfected with control vector, and from four replicates of PICALM knockout cells transfected with PICALM.

2015-06-17 | E-GEOD-64855 | biostudies-arrayexpress

Increase in membrane cholesterol of neurons in culture recapitulates AlzheimerM-bM-^@M-^Ys disease early phenotypes.

Project description:Levels of membrane-associated cholesterol were shown to be increased in the brain of individuals with sporadic AlzheimerM-bM-^@M-^Ys disease (AD) and correlated with the severity of the disease. We previously found that heavy membrane cholesterol burden promotes amyloid precursor protein (APP) endocytosis and processing, leading to increased amyloid-M-oM-^AM-"M-oM-^@M- M-oM-^@M-(AM-oM-^AM-") secretion. We hypothesized that such an increase of cholesterol could trigger sporadic AD. We thus acutely loaded the plasma membrane of neurons in culture with cholesterol to reach the 30 % increase observed in AD brains. We showed by multiplex electro-chemiluminescence immuno-assay that transient membrane cholesterol loading produced a significant increase of AM-oM-^AM-"42 secretion. We also found that early endosomes were enlarged and more prone to aggregation using confocal and electron microscopy and that APP vesicular transport in neuronal processes was slowed down using fluorescence live-imaging. In addition, treatment of neurons with cholesterol induced changes in gene expression profile that are reminiscent of early AD. This model of membrane cholesterol increase in cultured neurons reproduces most of early AD changes and could thus be relevant for deciphering early mechanisms and design new targets for sporadic AD. In this study, we loaded the plasma membrane of neurons with 30% more cholesterol and observed the effects on gene expression. We compared gene expression of primary hippocampal neurons treated or not with cholesterol using 4 independant replicates in each group.

2015-01-15 | E-GEOD-46221 | biostudies-arrayexpress

Peturbation of PICALM Levels Alters Cellular Cholesterol Metabolism

2015-06-17 | GSE64855 | GEO

The interactome of the UapA transporter reveals putative new players in anterograde membrane cargo trafficking: ΔartA: UapA-TurboID

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The interactome of the UapA transporter reveals putative new players in anterograde membrane cargo trafficking: UapA-DYDY TurboID

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