-
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 -
Current Opinion in Nephrology and... Jul 2013In this review, we discuss the role of endocytosis, a fundamental process internalizing molecules from the plasma membrane, and its critical importance in podocyte... (Review)
Review
PURPOSE OF REVIEW
In this review, we discuss the role of endocytosis, a fundamental process internalizing molecules from the plasma membrane, and its critical importance in podocyte biology.
RECENT FINDINGS
Endocytic clathrin and nonclathrin-coated pits have been visualized in podocytes using electron microscopy, but the functional biological relevance has not been well defined. Recent evidence suggests that loss of key clathrin endocytic regulatory apparatus, such as dynamin, synaptojanin 1 or endophilin, in genetic mouse models of disease results in severe proteinuria and foot process effacement. In addition, several genes implicated in human nephrotic syndrome directly or indirectly associate with these endocytic proteins, thus creating a protein network that is linked in actin dynamics, signalling and endocytosis.
SUMMARY
This review summarizes our current understanding of membrane trafficking specifically in podocytes, thus giving further novel insights into the molecular mechanisms and pathogenesis of nephrotic syndrome.
Topics: Actin Cytoskeleton; Animals; Clathrin-Coated Vesicles; Coated Pits, Cell-Membrane; Endocytosis; Humans; Nephrotic Syndrome; Podocytes; Protein Transport; Proteinuria; Signal Transduction
PubMed: 23703394
DOI: 10.1097/MNH.0b013e3283624820 -
The Journal of Cell Biology Sep 2020Clathrin-mediated endocytosis occurs via the assembly of clathrin-coated pits (CCPs) that invaginate and pinch off to form clathrin-coated vesicles (CCVs). It is well... (Review)
Review
Clathrin-mediated endocytosis occurs via the assembly of clathrin-coated pits (CCPs) that invaginate and pinch off to form clathrin-coated vesicles (CCVs). It is well known that adaptor protein 2 (AP2) complexes trigger clathrin assembly on the plasma membrane, and biochemical and structural studies have revealed the nature of these interactions. Numerous endocytic accessory proteins collaborate with clathrin and AP2 to drive CCV formation. However, many questions remain as to the molecular events involved in CCP initiation, stabilization, and curvature generation. Indeed, a plethora of recent evidence derived from cell perturbation, correlative light and EM tomography, live-cell imaging, modeling, and high-resolution structural analyses has revealed more complexity and promiscuity in the protein interactions driving CCP maturation than anticipated. After briefly reviewing the evidence supporting prevailing models, we integrate these new lines of evidence to develop a more dynamic and flexible model for how redundant, dynamic, and competing protein interactions can drive endocytic CCV formation and suggest new approaches to test emerging models.
Topics: Adaptor Protein Complex 2; Cell Membrane; Clathrin; Clathrin-Coated Vesicles; Coated Pits, Cell-Membrane; Endocytosis; Humans
PubMed: 32770195
DOI: 10.1083/jcb.202005126 -
Traffic (Copenhagen, Denmark) May 2004Most knowledge of clathrin-mediated endocytosis has been gained by biochemical fractionation and in vitro assays. Recently, the study of endocytosis has extended into... (Review)
Review
Most knowledge of clathrin-mediated endocytosis has been gained by biochemical fractionation and in vitro assays. Recently, the study of endocytosis has extended into the living cell. The tracking of individual clathrin-coated pits and vesicles (CCPs and CCVs) has provided new insight into understanding the dynamic nature of CCPs. The use of total internal reflection fluorescence microscopy (TIR-FM), also termed evanescent field microscopy, has enabled the direct observation of events occurring within a restricted area of the cell adjacent to and including the adherent plasma membrane. TIR-FM is now actively being pursued in the study of endocytic processes. The direct observation of CCP-associated proteins including clathrin itself, dynamin and, most recently, AP-2 has considerably challenged old models, confirming some points but raising very interesting new questions.
Topics: Adaptor Protein Complex 2; Animals; Clathrin; Coated Pits, Cell-Membrane; Endocytosis; Humans; Microscopy, Fluorescence; RNA, Small Interfering
PubMed: 15086782
DOI: 10.1111/j.1398-9219.2004.00187.x -
The EMBO Journal Sep 1987
Review
Topics: Animals; Clathrin; Coated Pits, Cell-Membrane; Endosomes; Models, Molecular; Protein Conformation
PubMed: 2890519
DOI: 10.1002/j.1460-2075.1987.tb02536.x -
Cold Spring Harbor Perspectives in... May 2014Clathrin is a molecular scaffold for vesicular uptake of cargo at the plasma membrane, where its assembly into cage-like lattices underlies the clathrin-coated pits of... (Review)
Review
Clathrin is a molecular scaffold for vesicular uptake of cargo at the plasma membrane, where its assembly into cage-like lattices underlies the clathrin-coated pits of classical endocytosis. This review describes the structures of clathrin, major cargo adaptors, and other proteins that participate in forming a clathrin-coated pit, loading its contents, pinching off the membrane as a lattice-enclosed vesicle, and recycling the components. It integrates as much of the structural information as possible at the time of writing into a sketch of the principal steps in coated-pit and coated-vesicle formation.
Topics: Actins; Animals; Auxilins; Biological Transport; Cell Membrane; Clathrin; Coated Pits, Cell-Membrane; Dynamins; Humans
PubMed: 24789820
DOI: 10.1101/cshperspect.a016725 -
Molecular Biology of the Cell Apr 2017Clathrin-mediated endocytosis (CME) is a fundamental process in cell biology and has been extensively investigated over the past several decades. Every cell biologist... (Review)
Review
Clathrin-mediated endocytosis (CME) is a fundamental process in cell biology and has been extensively investigated over the past several decades. Every cell biologist learns about it at some point during his or her education, and the beauty of this process has led many of us to go deeper and make it the topic of our research. Great progress has been made toward elucidating the mechanisms of CME, and the field is becoming increasingly complex, with several hundred new publications every year. This makes it easy to get lost in the vast amount of literature and forget about the fundamentals of the field, which are based on the careful interpretation of simple observations made >40 years ago, as exemplified by a study performed by Anderson, Brown, and Goldstein in 1977. We examine how this seminal study was pivotal to our understanding of CME and its progression into ever-increasing complexity over the past four decades.
Topics: Animals; Clathrin; Clathrin-Coated Vesicles; Coated Pits, Cell-Membrane; Endocytosis; Endosomes; History, 20th Century; Humans
PubMed: 28360213
DOI: 10.1091/mbc.E16-04-0213 -
The EMBO Journal Oct 2021Clathrin-coated pits are formed by the recognition of membrane and cargo by the AP2 complex and the subsequent recruitment of clathrin triskelia. A role for AP2 in...
Clathrin-coated pits are formed by the recognition of membrane and cargo by the AP2 complex and the subsequent recruitment of clathrin triskelia. A role for AP2 in coated-pit assembly beyond initial clathrin recruitment has not been explored. Clathrin binds the β2 subunit of AP2, and several binding sites have been identified, but our structural knowledge of these interactions is incomplete and their functional importance during endocytosis is unclear. Here, we analysed the cryo-EM structure of clathrin cages assembled in the presence of β2 hinge-appendage (β2HA). We find that the β2-appendage binds in at least two positions in the cage, demonstrating that multi-modal binding is a fundamental property of clathrin-AP2 interactions. In one position, β2-appendage cross-links two adjacent terminal domains from different triskelia. Functional analysis of β2HA-clathrin interactions reveals that endocytosis requires two clathrin interaction sites: a clathrin-box motif on the hinge and the "sandwich site" on the appendage. We propose that β2-appendage binding to more than one triskelion is a key feature of the system and likely explains why assembly is driven by AP2.
Topics: Adaptor Proteins, Vesicular Transport; Amino Acid Sequence; Binding Sites; Clathrin; Coated Pits, Cell-Membrane; Coated Vesicles; Endocytosis; Fluorescent Antibody Technique; HeLa Cells; Humans; Models, Molecular; Protein Binding; Protein Interaction Domains and Motifs; Protein Transport; Structure-Activity Relationship
PubMed: 34487371
DOI: 10.15252/embj.2021108795 -
Molecular Biology of the Cell Nov 2014Dynamin, the GTPase required for clathrin-mediated endocytosis, is recruited to clathrin-coated pits in two sequential phases. The first is associated with coated pit...
Dynamin, the GTPase required for clathrin-mediated endocytosis, is recruited to clathrin-coated pits in two sequential phases. The first is associated with coated pit maturation; the second, with fission of the membrane neck of a coated pit. Using gene-edited cells that express dynamin2-EGFP instead of dynamin2 and live-cell TIRF imaging with single-molecule EGFP sensitivity and high temporal resolution, we detected the arrival of dynamin at coated pits and defined dynamin dimers as the preferred assembly unit. We also used live-cell spinning-disk confocal microscopy calibrated by single-molecule EGFP detection to determine the number of dynamins recruited to the coated pits. A large fraction of budding coated pits recruit between 26 and 40 dynamins (between 1 and 1.5 helical turns of a dynamin collar) during the recruitment phase associated with neck fission; 26 are enough for coated vesicle release in cells partially depleted of dynamin by RNA interference. We discuss how these results restrict models for the mechanism of dynamin-mediated membrane scission.
Topics: Animals; Base Sequence; Cattle; Cell Line, Tumor; Clathrin; Clathrin-Coated Vesicles; Coated Pits, Cell-Membrane; Dynamin II; Dynamins; Endocytosis; Gene Expression Regulation; Genes, Reporter; Green Fluorescent Proteins; Humans; Microscopy, Fluorescence; Models, Molecular; Molecular Sequence Data; Protein Multimerization; Protein Transport; RNA, Small Interfering; Signal Transduction
PubMed: 25232009
DOI: 10.1091/mbc.E14-07-1240 -
Biochimica Et Biophysica Acta Apr 2009Epithelial cells form a barrier against the environment, but are also required for the regulated exchange of molecules between an organism and its surroundings.... (Review)
Review
Epithelial cells form a barrier against the environment, but are also required for the regulated exchange of molecules between an organism and its surroundings. Epithelial cells are characterised by a remarkable polarization of their plasma membrane, evidenced by the appearance of structurally, compositionally, and functionally distinct surface domains. Here we consider the (in)dependence of epithelial cell polarisation and the function of smaller plasma membrane domains (e.g. adherens junctions, gap junctions, tight junctions, apical lipid rafts, caveolae, and clathrin-coated pits) in the development and maintenance of cell surface polarity. Recent evidence of cross-talk and/or overlap between the different cell-cell junction components and alternate functions of junction components, including gene expression regulation, are discussed in the context of cell surface polarity.
Topics: Adherens Junctions; Animals; Caveolae; Cell Adhesion; Cell Membrane; Cell Polarity; Coated Pits, Cell-Membrane; Desmosomes; Epithelial Cells; Gap Junctions; Humans; Lipid Bilayers; Membrane Microdomains; Signal Transduction; Tight Junctions
PubMed: 18706883
DOI: 10.1016/j.bbamem.2008.07.015