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Annual Review of Biochemistry Jun 2018Clathrin-mediated endocytosis (CME) is the major endocytic pathway in mammalian cells. It is responsible for the uptake of transmembrane receptors and transporters, for... (Review)
Review
Clathrin-mediated endocytosis (CME) is the major endocytic pathway in mammalian cells. It is responsible for the uptake of transmembrane receptors and transporters, for remodeling plasma membrane composition in response to environmental changes, and for regulating cell surface signaling. CME occurs via the assembly and maturation of clathrin-coated pits that concentrate cargo as they invaginate and pinch off to form clathrin-coated vesicles. In addition to the major coat proteins, clathrin triskelia and adaptor protein complexes, CME requires a myriad of endocytic accessory proteins and phosphatidylinositol lipids. CME is regulated at multiple steps-initiation, cargo selection, maturation, and fission-and is monitored by an endocytic checkpoint that induces disassembly of defective pits. Regulation occurs via posttranslational modifications, allosteric conformational changes, and isoform and splice-variant differences among components of the CME machinery, including the GTPase dynamin. This review summarizes recent findings on the regulation of CME and the evolution of this complex process.
Topics: Adaptor Protein Complex 2; Allosteric Regulation; Animals; Clathrin; Clathrin-Coated Vesicles; Dynamins; Endocytosis; Evolution, Molecular; Humans; Models, Biological; Phosphatidylinositol Phosphates; Phosphorylation; Protein Conformation; Signal Transduction
PubMed: 29661000
DOI: 10.1146/annurev-biochem-062917-012644 -
Journal of Controlled Release :... Nov 2017Recent evidence has established that extracellular vesicles (EVs), including exosomes and microvesicles, form an endogenous transport system through which biomolecules,...
Recent evidence has established that extracellular vesicles (EVs), including exosomes and microvesicles, form an endogenous transport system through which biomolecules, including proteins and RNA, are exchanged between cells. This endows EVs with immense potential for drug delivery and regenerative medicine applications. Understanding the biology underlying EV-based intercellular transfer of cargo is of great importance for the development of EV-based therapeutics. Here, we sought to characterize the cellular mechanisms involved in EV uptake. Internalization of fluorescently-labeled EVs was evaluated in HeLa cells, in 2D (monolayer) cell culture as well as 3D spheroids. Uptake was assessed using flow cytometry and confocal microscopy, using chemical as well as RNA interference-based inhibition of key proteins involved in individual endocytic pathways. Experiments with chemical inhibitors revealed that EV uptake depends on cholesterol and tyrosine kinase activity, which are implicated in clathrin-independent endocytosis, and on Na/H exchange and phosphoinositide 3-kinase activity, which are important for macropinocytosis. Furthermore, EV internalization was inhibited by siRNA-mediated knockdown of caveolin-1, flotillin-1, RhoA, Rac1 and PAK1, but not clathrin heavy chain. Together, these results suggest that EVs enter cells predominantly via clathrin-independent endocytosis and macropinocytosis. Identification of EV components that promote their uptake via pathways that lead to functional cargo transfer might allow development of more efficient therapeutics through EV-inspired engineering.
Topics: Cell Line, Tumor; Clathrin; Endocytosis; Extracellular Vesicles; Humans; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Nanoparticles; Phosphate-Binding Proteins; RNA, Small Interfering; Spheroids, Cellular
PubMed: 28919558
DOI: 10.1016/j.jconrel.2017.09.019 -
F1000Research 2019Endocytic pathways are broadly classified into clathrin dependent and independent on the basis of the requirement for the coat protein, clathrin. The molecular pathways... (Review)
Review
Endocytic pathways are broadly classified into clathrin dependent and independent on the basis of the requirement for the coat protein, clathrin. The molecular pathways and mechanisms underlying the formation of clathrin-independent pathways are still being explored, and this review summarizes recent advances and emerging functional roles of these diverse pathways. In particular, this review will discuss the growing consensus on the role of BAR domain proteins and the actin machinery in different clathrin-independent pathways and its significance to the functions fulfilled by these endocytic pathways.
Topics: Actins; Clathrin; Endocytosis; Metabolic Networks and Pathways
PubMed: 30774931
DOI: 10.12688/f1000research.16549.1 -
Biochimica Et Biophysica Acta Aug 1998Clathrin and adaptors are components of clathrin-coated pits and vesicles. The AP-1 adaptor complex is associated with clathrin-coated vesicles budding from the TGN,... (Review)
Review
Clathrin and adaptors are components of clathrin-coated pits and vesicles. The AP-1 adaptor complex is associated with clathrin-coated vesicles budding from the TGN, while the AP-2 adaptor complex is associated with clathrin-coated vesicles budding from the plasma membrane. The clathrin forms a polyhedral lattice and is believed to be the driving force behind membrane invagination leading to vesicle budding. The adaptors attach the clathrin to the membrane and also interact with the cytoplasmic domains of selected transmembrane proteins, causing these proteins to become concentrated in clathrin-coated vesicles. Clathrin-coated vesicles budding from the TGN have been implicated in the sorting of newly synthesised lysosomal enzymes, while clathrin-coated vesicles budding from the plasma membrane facilitate the receptor-mediated endocytosis of ligands, such as low density lipoproteins and transferrin. A novel adaptor-related complex, AP-3, has recently been identified, which is recruited onto membranes of the TGN and a more peripheral compartment but does not appear to be associated with clathrin. Genetic studies indicate that AP-3 plays a role in the sorting of proteins to lysosomes and lysosome-related organelles.
Topics: Adaptor Protein Complex 3; Adaptor Protein Complex alpha Subunits; Adaptor Protein Complex delta Subunits; Adaptor Proteins, Vesicular Transport; Animals; Clathrin; Humans; Membrane Proteins; Monomeric Clathrin Assembly Proteins; Transcription Factors
PubMed: 9714795
DOI: 10.1016/s0167-4889(98)00056-1 -
Current Opinion in Structural Biology Aug 2022Clathrin-mediated endocytosis enables selective uptake of molecules into cells in response to changing cellular needs. It occurs through assembly of coat components... (Review)
Review
Clathrin-mediated endocytosis enables selective uptake of molecules into cells in response to changing cellular needs. It occurs through assembly of coat components around the plasma membrane that determine vesicle contents and facilitate membrane bending to form a clathrin-coated transport vesicle. In this review we discuss recent cryo-electron microscopy structures that have captured a series of events in the life cycle of a clathrin-coated vesicle. Both single particle analysis and tomography approaches have revealed details of the clathrin lattice structure itself, how AP2 may interface with clathrin within a coated vesicle and the importance of PIP2 binding for assembly of the yeast adaptors Sla2 and Ent1 on the membrane. Within cells, cryo-electron tomography of clathrin in flat lattices and high-speed AFM studies provided new insights into how clathrin morphology can adapt during CCV formation. Thus, key mechanical processes driving clathrin-mediated endocytosis have been captured through multiple techniques working in partnership.
Topics: Cell Membrane; Clathrin; Clathrin-Coated Vesicles; Coated Vesicles; Cryoelectron Microscopy; Endocytosis; Saccharomyces cerevisiae
PubMed: 35872561
DOI: 10.1016/j.sbi.2022.102427 -
Molecular Aspects of Medicine Feb 2022Endocytosis mechanisms are one of the methods that cells use to interact with their environments. Endocytosis mechanisms vary from the clathrin-mediated endocytosis to... (Review)
Review
Endocytosis mechanisms are one of the methods that cells use to interact with their environments. Endocytosis mechanisms vary from the clathrin-mediated endocytosis to the receptor independent macropinocytosis. Macropinocytosis is a niche of endocytosis that is quickly becoming more relevant in various fields of research since its discovery in the 1930s. Macropinocytosis has several distinguishing factors from other receptor-mediated forms of endocytosis, including: types of extracellular material for uptake, signaling cascade, and niche uses between cell types. Nanoparticles (NPs) are an important tool for various applications, including drug delivery and disease treatment. However, surface engineering of NPs could be tailored to target them inside the cells exploiting different endocytosis pathways, such as endocytosis versus macropinocytosis. Such surface engineering of NPs mainly, size, charge, shape and the core material will allow identification of new adapter molecules regulating different endocytosis process and provide further insight into how cells tweak these pathways to meet their physiological need. In this review, we focus on the description of macropinocytosis, a lesser studied endocytosis mechanism than the conventional receptor mediated endocytosis. Additionally, we will discuss nanoparticle endocytosis (including macropinocytosis), and how the physio-chemical properties of the NP (size, charge, and surface coating) affect their intracellular uptake and exploiting them as tools to identify new adapter molecules regulating these processes.
Topics: Biological Transport; Clathrin; Endocytosis; Humans; Nanoparticles; Pinocytosis
PubMed: 34281720
DOI: 10.1016/j.mam.2021.100993 -
Traffic (Copenhagen, Denmark) Dec 2015The purification of coated vesicles and the discovery of clathrin by Barbara Pearse in 1975 was a landmark in cell biology. Over the past 40 years, work from many labs... (Review)
Review
The purification of coated vesicles and the discovery of clathrin by Barbara Pearse in 1975 was a landmark in cell biology. Over the past 40 years, work from many labs has uncovered the molecular details of clathrin and its associated proteins, including how they assemble into a coated vesicle and how they select cargo. Unexpected connections have been found with signalling, development, neuronal transmission, infection, immunity and genetic disorders. But there are still a number of unanswered questions, including how clathrin-mediated trafficking is regulated and how the machinery evolved.
Topics: Animals; Cell Biology; Clathrin; Clathrin-Coated Vesicles; Coated Pits, Cell-Membrane; History, 20th Century; History, 21st Century; Humans; Models, Molecular; Protein Conformation; Protein Transport
PubMed: 26403691
DOI: 10.1111/tra.12335 -
Emerging Microbes & Infections Dec 2023African swine fever (ASF) is a highly contagious and acute hemorrhagic viral disease with high morbidity and mortality in domestic pigs and wild boars. The disease has...
African swine fever (ASF) is a highly contagious and acute hemorrhagic viral disease with high morbidity and mortality in domestic pigs and wild boars. The disease has become a global threat to the pig production industry and has caused enormous economic losses in many countries in recent years. However, the molecular mechanism underlying ASF virus (ASFV) entry of the host cells is not fully understood, which restricts the development of vaccines and antiviral-drugs of ASFV. In this study, we found that the host protein CD1d acts as a host factor, which mediates ASFV entry into the host cells. As the main capsid protein on the surface of ASFV virions, p72 can mediate viral entry. Using IP-MS assay, CD1d was identified as a binding partner of p72 on surface of ASFV virions. Knockdown of CD1d expression and blocking the cells with anti-pCD1d antibody, or incubating ASFV virions with soluble CD1d protein could significantly inhibit ASFV infection. CD1d is located on the membrane surface of primary porcine alveolar macrophages (PAMs) and mediates the virus entry via binding to p72. CD1d knockout or CD1d knockdown assay showed that CD1d could facilitate ASFV virions internalization via clathrin-mediated endocytosis (CME). Furthermore, CD1d interacts with EPS15 to mediate ASFV entry via clathrin-mediated endocytosis. Overall, our findings revealed that CD1d is a novel host-entry factor involved in ASFV internalization via the EPS15-clathrin endocytosis axis and a potential target for antiviral intervention.
Topics: Swine; Animals; African Swine Fever Virus; African Swine Fever; Endocytosis; Sus scrofa; Clathrin
PubMed: 37254454
DOI: 10.1080/22221751.2023.2220575 -
FEBS Letters Sep 2022Endocytic trafficking underlies processes essential for plant growth and development, including the perception of and response to abiotic and extracellular stimuli,... (Review)
Review
Endocytic trafficking underlies processes essential for plant growth and development, including the perception of and response to abiotic and extracellular stimuli, post-Golgi and exocytic trafficking, and cytokinesis. Protein adaptors and regulatory factors of clathrin-mediated endocytosis that contribute to the formation of endocytic clathrin-coated vesicles are evolutionarily conserved. Yet, work of the last ten years has identified differences between the endocytic mechanisms of plants and Opisthokonts involving the endocytic adaptor TPLATE complex, the requirement of actin during CME, and the function of clathrin-independent endocytosis in the uptake of plant-specific plasma membrane proteins. Here, we review clathrin-mediated and -independent pathways in plants and describe recent advances enabled by new proteomic and imaging methods, and conditional perturbation of endocytosis. In addition, we summarize the formation and trafficking of clathrin-coated vesicles based on temporal and structural data garnered from high-resolution quantitative imaging studies. Finally, new information about the cross-talk between endocytosis and other endomembrane trafficking pathways and organelles will also be discussed.
Topics: Clathrin; Clathrin-Coated Vesicles; Cytokinesis; Endocytosis; Proteomics
PubMed: 35674447
DOI: 10.1002/1873-3468.14420 -
The Journal of Cell Biology Jul 2022Cell biologists have long debated the role of clathrin in curving membranes during endocytosis. New findings from Cail et al. (2022. J. Cell...
Cell biologists have long debated the role of clathrin in curving membranes during endocytosis. New findings from Cail et al. (2022. J. Cell Biol.https://doi.org/10.1083/jcb.202109013) take an innovative approach to directly demonstrate the indispensable functions of both clathrin and its adaptor network in shaping endocytic vesicles.
Topics: Clathrin; Endocytosis; Transport Vesicles
PubMed: 35704021
DOI: 10.1083/jcb.202206014