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1.
Methods Mol Biol ; 2591: 283-295, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36350555

RESUMO

Ubiquitin modification is known to regulate endocytic trafficking of many different types of cargo in eukaryotic cells, but it can be challenging to determine what role, if any, ubiquitin plays in the trafficking of a novel or uncharacterized endocytic cargo. Here, we describe a useful approach that leverages fusion to deubiquitinase (DUB) catalytic domains to explore the role ubiquitin plays in endocytic trafficking. This approach can be applied to the analysis of many different endocytic cargos in different cell types, and it can also be used to study linkage specificity in endocytic trafficking. Several different trafficking assays are described to illustrate the broad utility of this "DUB fusion" approach.


Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Endocitose/fisiologia , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Ubiquitina/metabolismo , Enzimas Desubiquitinantes/genética , Enzimas Desubiquitinantes/metabolismo
2.
J Cell Biol ; 222(1)2023 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-36250940

RESUMO

Integrin endocytosis is essential for many fundamental cellular processes. Whether and how the internalization impacts cellular mechanics remains elusive. Whereas previous studies reported the contribution of the integrin activator, talin, in force development, the involvement of inhibitors is less documented. We identified ICAP-1 as an integrin inhibitor involved in mechanotransduction by co-working with NME2 to control clathrin-mediated endocytosis of integrins at the edge of focal adhesions (FA). Loss of ICAP-1 enables ß3-integrin-mediated force generation independently of ß1 integrin. ß3-integrin-mediated forces were associated with a decrease in ß3 integrin dynamics stemming from their reduced diffusion within adhesion sites and slow turnover of FA. The decrease in ß3 integrin dynamics correlated with a defect in integrin endocytosis. ICAP-1 acts as an adaptor for clathrin-dependent endocytosis of integrins. ICAP-1 controls integrin endocytosis by interacting with NME2, a key regulator of dynamin-dependent clathrin-coated pits fission. Control of clathrin-mediated integrin endocytosis by an inhibitor is an unprecedented mechanism to tune forces at FA.


Assuntos
Clatrina , Endocitose , Adesões Focais , Integrina beta1 , Integrina beta3 , Clatrina/metabolismo , Endocitose/fisiologia , Integrina beta1/genética , Mecanotransdução Celular , Talina/genética
3.
Methods Mol Biol ; 2587: 513-526, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36401047

RESUMO

Plasma membrane injury activates membrane trafficking and remodeling events that are required for the injured membrane to repair. With the rapidity of the membrane repair process, the repair response needs to be monitored at high temporal and spatial resolution. In this chapter, we describe the use of live cell optical imaging approaches to monitor injury-triggered bulk and individual vesicle endocytosis. Use of these approaches allows quantitatively assessment of the rate of retrieval of the injured plasma membrane by bulk endocytosis as well as by endocytosis of individual caveolae following plasma membrane injury.


Assuntos
Endocitose , Vesículas Sinápticas , Membrana Celular/metabolismo , Vesículas Sinápticas/metabolismo
4.
Methods Mol Biol ; 2603: 43-58, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36370269

RESUMO

The protein cargo of extracellular vesicles (EVs) determines their impact on recipient cell types and the downstream effects on biological function. Environmental cues can modify EV loading with proteins derived from the plasma membrane via endocytosis, obtained from the preexisting cytosolic pool via active sorting, or packaging with newly synthesized proteins drawn from trans-golgi networks. Given the major impact these pathways exert on EV content and functional potential, it is important to study how defined stimuli influence protein sorting into these vesicles for dispersal. To this end, pSILAC-based approaches can be used to pulse/trace the origins of EV protein content and thereby provide valuable insight into vesicle biology and likely effects on intercellular communication in diverse settings.


Assuntos
Vesículas Extracelulares , Vesículas Extracelulares/metabolismo , Transporte Proteico , Comunicação Celular , Proteínas/metabolismo , Endocitose
5.
Methods Mol Biol ; 2565: 77-87, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36205888

RESUMO

Recent advances in stimulated emission depletion (STED) microscopy offer an unparalleled avenue to study membrane dynamics of exo- and endocytosis, such as fusion pore opening, pore expansion, constriction, and closure, as well as the membrane transformation from flat-shaped to round-shaped vesicles in real time. Here we depict a method of using the state-of-the-art STED microscopy to image these membrane dynamics in bovine chromaffin cells. This method can potentially be applied to study other membrane structure dynamics in other cell model system.


Assuntos
Células Cromafins , Microscopia , Animais , Bovinos , Membrana Celular/metabolismo , Endocitose , Vesículas Secretórias/metabolismo
6.
J R Soc Interface ; 19(196): 20220462, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36321371

RESUMO

Cellular uptake through membranes plays an important role in adsorbing nutrients and fighting infection and can be used for nanomedicine developments. Endocytosis is one of the pathways of cellular uptake which associate with elastic deformation of the membrane wrapping around the foreign particle. The deformability of the membrane is strongly regulated by the presence of a cortical cytoskeleton placed underneath the membrane. It is shown that shape and orientation of the particles influence on their internalization. Here, we study the role of particle local curvature in cellular uptake by investigating the wrapping of an elastic membrane around a long cylindrical object with an elliptical cross-section. The membrane itself is adhered to a substrate mimicking the cytoskeleton. Membrane wrapping proceeds differently whether the initial contact occurs at the target's highly curved part (vertical) or along its long side (horizontal). We obtain a wrapping phase diagram as a function of the membrane-cytoskeleton and the membrane-target adhesion energy, which includes three distinct regimes (unwrapped, partially wrapped and fully wrapped), separated by two phase transitions. We also provide analytical expressions for the boundaries between the different regimes which confirm that the transitions strongly depend on the orientation and aspect ratio of the nanowire.


Assuntos
Endocitose , Nanofios , Citoesqueleto/metabolismo , Transporte Biológico , Membrana Celular/metabolismo
7.
Nat Commun ; 13(1): 6589, 2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36329028

RESUMO

Receptor Tyrosine Kinase (RTK) endocytosis-dependent signalling drives cell proliferation and motility during development and adult homeostasis, but is dysregulated in diseases, including cancer. The recruitment of RTK signalling partners during endocytosis, specifically during recycling to the plasma membrane, is still unknown. Focusing on Fibroblast Growth Factor Receptor 2b (FGFR2b) recycling, we reveal FGFR signalling partners proximal to recycling endosomes by developing a Spatially Resolved Phosphoproteomics (SRP) approach based on APEX2-driven biotinylation followed by phosphorylated peptides enrichment. Combining this with traditional phosphoproteomics, bioinformatics, and targeted assays, we uncover that FGFR2b stimulated by its recycling ligand FGF10 activates mTOR-dependent signalling and ULK1 at the recycling endosomes, leading to autophagy suppression and cell survival. This adds to the growing importance of RTK recycling in orchestrating cell fate and suggests a therapeutically targetable vulnerability in ligand-responsive cancer cells. Integrating SRP with other systems biology approaches provides a powerful tool to spatially resolve cellular signalling.


Assuntos
Endossomos , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismo , Ligantes , Endossomos/metabolismo , Endocitose/fisiologia , Autofagia , Fator 10 de Crescimento de Fibroblastos/metabolismo
8.
Sci Rep ; 12(1): 18572, 2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36329148

RESUMO

Trypanosoma brucei causes human African trypanosomiasis (HAT) and nagana in cattle. During infection of a vertebrate, endocytosis of host transferrin (Tf) is important for viability of the parasite. The majority of proteins involved in trypanosome endocytosis of Tf are unknown. Here we identify pseudokinase NRP1 (Tb427tmp.160.4770) as a regulator of Tf endocytosis. Genetic knockdown of NRP1 inhibited endocytosis of Tf without blocking uptake of bovine serum albumin. Binding of Tf to the flagellar pocket was not affected by knockdown of NRP1. However the quantity of Tf per endosome dropped significantly, consistent with NRP1 promoting robust capture and/or retention of Tf in vesicles. NRP1 is involved in motility of Tf-laden vesicles since distances between endosomes and the kinetoplast were reduced after knockdown of the gene. In search of possible mediators of NRP1 modulation of Tf endocytosis, the gene was knocked down and the phosphoproteome analyzed. Phosphorylation of protein kinases forkhead, NEK6, and MAPK10 was altered, in addition to EpsinR, synaptobrevin and other vesicle-associated proteins predicted to be involved in endocytosis. These candidate proteins may link NRP1 functionally either to protein kinases or to vesicle-associated proteins.


Assuntos
Trypanosoma brucei brucei , Trypanosoma , Tripanossomíase Africana , Animais , Bovinos , Humanos , Endocitose/genética , Endossomos/metabolismo , Quinases Relacionadas a NIMA/metabolismo , Proteínas Quinases/metabolismo , Receptores da Transferrina/metabolismo , Transferrina/genética , Transferrina/metabolismo , Trypanosoma/metabolismo , Trypanosoma brucei brucei/metabolismo , Tripanossomíase Africana/parasitologia , Neuropilina-1/metabolismo
9.
Dokl Biochem Biophys ; 506(1): 206-209, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36303053

RESUMO

In the present manuscript we analyzed the influence of hypoxic response in Caco-2 cells on the expression of genes and miRNAs involved in the mechanisms of intracellular transport of SARS-CoV-2 viral particles, especially endocytosis and transcytosis. With the use of RNA sequencing of Caco-2 cells treated with hypoxia-inducing oxyquinoline derivative, we showed two-fold increase in the expression of the main SARS-CoV-2 receptor ACE2. Expression of the non-canonical receptor TFRC was also elevated. We also observed a significant increase in the expression levels of genes from the low-density lipoprotein (LDL) receptor family, which play a crucial role in the transcytosis: LDLR, LRP1, LRP4, and LRP5. Upregulation of LDLR was coupled with the downregulation of hsa-miR-148a-3p, which can directly bind to LDLR mRNA. Thus, the hypoxic response in Caco-2 cells includes upregulation of genes involved in the mechanisms of endocytosis and transcytosis of SARS-CoV-2 viral particles.


Assuntos
COVID-19 , Hipóxia Celular , Endocitose , Transcitose , Humanos , Células CACO-2 , MicroRNAs/genética , SARS-CoV-2
10.
J Nanobiotechnology ; 20(1): 458, 2022 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-36303212

RESUMO

BACKGROUND: Although protein-based methods using cell-penetrating peptides such as TAT have been expected to provide an alternative approach to siRNA delivery, the low efficiency of endosomal escape of siRNA/protein complexes taken up into cells by endocytosis remains a problem. Here, to overcome this problem, we adopted the membrane penetration-enhancing peptide S19 from human syncytin 1 previously identified in our laboratory. RESULTS: We prepared fusion proteins in which the S19 and TAT peptides were fused to the viral RNA-binding domains (RBDs) as carrier proteins, added the RBD-S19-TAT/siRNA complex to human cultured cells, and investigated the cytoplasmic delivery of the complex and the knockdown efficiency of target genes. We found that the intracellular uptake of the RBD-S19-TAT/siRNA complex was increased compared to that of the RBD-TAT/siRNA complex, and the expression level of the target mRNA was decreased. Because siRNA must dissociate from RBD and bind to Argonaute 2 (Ago2) to form the RNA-induced silencing complex (RISC) after the protein/siRNA complex is delivered into the cytoplasm, a dilemma arises: stronger binding between RBD and siRNA increases intracellular uptake but makes RISC formation more difficult. Thus, we next prepared fusion proteins in which the S19 and TAT peptides were fused with Ago2 instead of RBD and found that the efficiencies of siRNA delivery and knockdown obtained using TAT-S19-Ago2 were higher than those using TAT-Ago2. In addition, we found that the smallest RISC delivery induced faster knockdown than traditional siRNA lipofection, probably due to the decreased time required for RISC formation in the cytoplasm. CONCLUSION: These results indicated that S19 and TAT-fused siRNA-binding proteins, especially Ago2, should be useful for the rapid and efficient delivery of siRNA without the addition of any endosome-disrupting agent.


Assuntos
Peptídeos Penetradores de Células , Humanos , RNA Interferente Pequeno/genética , Peptídeos Penetradores de Células/química , Endossomos/metabolismo , Endocitose , Linhagem Celular
11.
Neurol Res ; 44(11): 1024-1037, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36217917

RESUMO

OBJECTIVE: Secretory carrier membrane proteins (SCAMPs) constitute a group of membrane transport proteins in plants, insects and mammals. The mammalian genome contains five types of SCAMP genes, namely, SCAMP1-SCAMP5. SCAMPs participate in the vesicle cycling fusion of vesicles and cell membranes and play roles in regulating exocytosis and endocytosis, activating synaptic function and transmitting nerve signals. Among these proteins, SCAMP5 is highly expressed in the brain and has direct or indirect effects on the function of the central nervous system. This paper may allow us to better understand the role of SCAMP5 in the central nervous system diseases. SCAMP5 regulates membrane transport, controls the exocytosis of SVs and is related to secretion carrier and membrane function. In addition, SCAMP5 plays a major role in the normal maintenance of the physiological functions of nerve cells. This article summarizes the effects of SCAMP5 on nerve cell exocytosis, endocytosis and synaptic function, as well as the relationship between SCAMP5 and various neurological diseases, to better understand the role of SCAMP5 in the pathogenesis of neurological diseases. METHODS: Through PubMed, this paper examined and analyzed the role of SCAMP5 in the central nervous system, as well as the relationship between SCAMP5 and various neurological diseases using the key terms "secretory carrier membrane proteins"," SCAMP5"," exocytosis"," endocytosis", "synaptic function", "central nervous system diseases" up to 01 March 2022. RESULTS: SCAMP5 regulates membrane transport, controls the exocytosis of SVs and is related to secretion carrier and membrane function. In addition, SCAMP5 plays a major role in the normal maintenance of the physiological functions of nerve cells. CONCLUSION: This article summarizes the effects of SCAMP5 on nerve cell exocytosis, endocytosis and synaptic function, as well as the relationship between SCAMP5 and various neurological diseases, to better understand the role of SCAMP5 in the pathogenesis of neurological diseases.


Assuntos
Proteínas de Transporte , Proteínas de Membrana , Animais , Proteínas de Transporte/genética , Proteínas de Membrana/metabolismo , Exocitose , Membrana Celular/metabolismo , Endocitose/genética , Mamíferos/metabolismo
12.
Proc Natl Acad Sci U S A ; 119(43): e2207280119, 2022 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-36252040

RESUMO

The current view of nucleic acid-mediated innate immunity is that binding of intracellular sensors to nucleic acids is sufficient for their activation. Here, we report that endocytosis of virus or foreign DNA initiates a priming signal for the DNA sensor cyclic GMP-AMP synthase (cGAS)-mediated innate immune response. Mechanistically, viral infection or foreign DNA transfection triggers recruitment of the spleen tyrosine kinase (SYK) and cGAS to the endosomal vacuolar H+ pump (V-ATPase), where SYK is activated and then phosphorylates human cGASY214/215 (mouse cGasY200/201) to prime its activation. Upon binding to DNA, the primed cGAS initiates robust cGAMP production and mediator of IRF3 activation/stimulator of interferon genes-dependent innate immune response. Consistently, blocking the V-ATPase-SYK axis impairs DNA virus- and transfected DNA-induced cGAMP production and expression of antiviral genes. Our findings reveal that V-ATPase-SYK-mediated tyrosine phosphorylation of cGAS following endocytosis of virus or other cargos serves as a priming signal for cGAS activation and innate immune response.


Assuntos
Endocitose , Imunidade Inata , Nucleotidiltransferases , Quinase Syk , ATPases Vacuolares Próton-Translocadoras , Animais , Humanos , Camundongos , DNA , Interferons/metabolismo , Proteínas de Membrana/metabolismo , Nucleotidiltransferases/metabolismo , Transdução de Sinais/genética , Quinase Syk/metabolismo , Tirosina , ATPases Vacuolares Próton-Translocadoras/metabolismo
13.
Viruses ; 14(10)2022 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-36298756

RESUMO

Caveolin-1 (Cav-1) is the basic component of caveolae, a specialized form of lipid raft that plays an essential role in endocytic viral entry. However, the evidence of direct involvement of caveolae and Cav-1 in avian reovirus (ARV) entry remains insufficient. In this study, the membrane lipid rafts were isolated as detergent-resistant microdomains (DRMs) by sucrose gradient centrifugation, and the capsid protein σB of ARV was found to associate with Cav-1 in DRMs fractions. Additionally, the interaction between ARV σB protein and Cav-1 was demonstrated by immunofluorescence co-localization and co-immunoprecipitation assays. Furthermore, we found that the internalization of ARV is sensitive to caveolae and dynamin inhibitors, while it is insensitive to clathrin inhibitors. In conclusion, these results indicate that the ARV σB protein interacts with Cav-1 during dynamin-dependent caveolae-mediated endocytosis for the entry of ARV.


Assuntos
Caveolina 1 , Orthoreovirus Aviário , Caveolina 1/metabolismo , Cavéolas/metabolismo , Detergentes , Proteínas do Capsídeo/metabolismo , Microdomínios da Membrana/metabolismo , Endocitose , Clatrina/metabolismo , Dinaminas/metabolismo , Sacarose/metabolismo , Lipídeos de Membrana/metabolismo
14.
Biochem Soc Trans ; 50(5): 1257-1267, 2022 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-36214373

RESUMO

Continuous reshaping of the plasma membrane into pleomorphic shapes is critical for a plethora of cellular functions. How the cell carries out this enigmatic control of membrane remodeling has remained an active research field for decades and several molecular and biophysical mechanisms have shown to be involved in overcoming the energy barrier associated with membrane bending. The reported mechanisms behind membrane bending have been largely concerned with structural protein features, however, in the last decade, reports on the ability of densely packed proteins to bend membranes by protein-protein crowding, have challenged prevailing mechanistic views. Crowding has now been shown to generate spontaneous vesicle formation and tubular morphologies on cell- and model membranes, demonstrating crowding as a relevant player involved in the bending of membranes. Still, current research is largely based on unnatural overexpression of proteins in non-native domains, and together with efforts in modeling, this has led to questioning the in vivo impact of crowding. In this review, we examine this previously overlooked mechanism by summarizing recent advances in the understanding of protein-protein crowding and its prevalence in cellular membrane-shaping processes.


Assuntos
Endocitose , Proteínas de Membrana , Proteínas de Membrana/metabolismo , Membrana Celular/metabolismo , Biofísica
15.
PLoS Genet ; 18(10): e1010296, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36279308

RESUMO

After endocytosis, transmembrane cargo is differentially sorted into degradative or recycling pathways. This process is facilitated by recruitment into physically distinct degradative or recycling microdomains on the limiting membrane of individual endosomes. Endosomal sorting complexes required for transport (ESCRT) mark the degradative microdomain, while the recycling domain is marked by the retromer complex and associated proteins RME-8 and SNX-1. The separation of endosomal microdomains is also controlled by RME-8 and SNX-1, at least in part via removal of degradative component HRS/HGRS-1 from the recycling microdomain. This activity is likely due to recruitment and activation of chaperone Hsc70 on the endosome by the RME-8 DNAJ domain. To better understand the mechanism of RME-8 function we performed a new phylogenetic analysis of RME-8 and identified new conserved sequence features. In a complementary approach, we performed structure-function analysis that identified the C-terminus as important for microdomain localization and likely substrate binding, while N-terminal sequences beyond the known single N-terminal PH-like domain are important for endosome recruitment. Random mutagenesis identified IWN4, and by analogy IWN3, to be important for the autoinhibitory DNAJ domain binding, with IWN3 playing a critical role in HRS uncoating activity. Combining AlphaFold structural predictions with in vivo mutation analysis of RME-8, we propose a model whereby SNX-1 and the IWN domains control the conformation of RME-8 and hence the productive exposure of the DNAJ domain. Furthermore, we propose that the activation of RME-8 is cyclical, with SNX-1 acting as an activator and a target of RME-8 uncoating activity.


Assuntos
Endocitose , Endossomos , Filogenia , Endossomos/genética , Endossomos/metabolismo , Transporte Proteico , Mutagênese , Nexinas de Classificação/genética
16.
J Am Chem Soc ; 144(44): 20288-20297, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36301712

RESUMO

Delivering cargo molecules across the plasma membrane is critical for biomedical research, and the need to develop molecularly well-defined tags that enable cargo transportation is ever-increasing. We report here a hydrophilic endocytosis-promoting peptide (EPP6) rich in hydroxyl groups with no positive charge. EPP6 can transport a wide array of small-molecule cargos into a diverse panel of animal cells. Mechanistic studies revealed that it entered the cells through a caveolin- and dynamin-dependent endocytosis pathway, mediated by the surface receptor fibrinogen C domain-containing protein 1. After endocytosis, EPP6 trafficked through early and late endosomes within 30 min. Over time, EPP6 partitioned among cytosol, lysosomes, and some long-lived compartments. It also demonstrated prominent transcytosis abilities in both in vitro and in vivo models. Our study proves that positive charge is not an indispensable feature for hydrophilic cell-penetrating peptides and provides a new category of molecularly well-defined delivery tags for biomedical applications.


Assuntos
Peptídeos Penetradores de Células , Endocitose , Animais , Endossomos/metabolismo , Peptídeos Penetradores de Células/metabolismo , Lisossomos/metabolismo , Interações Hidrofóbicas e Hidrofílicas
17.
Development ; 149(19)2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36189830

RESUMO

Within a cell, vesicles play a crucial role in the transport of membrane material and proteins to a given target membrane, and thus regulate a variety of cellular functions. Vesicular transport occurs by means of, among others, endocytosis, where cargoes are taken up by the cell and are processed further upon vesicular trafficking, i.e. transported back to the plasma membrane via recycling endosomes or the degraded by fusion of the vesicles with lysosomes. During evolution, a variety of vesicles with individual functions arose, with some of them building up highly specialised subcellular compartments. In this study, we have analysed the biosynthesis of a new vesicular compartment present in the valve cells of Drosophila melanogaster. We show that the compartment is formed by invaginations of the plasma membrane and grows via re-routing of the recycling endosomal pathway. This is achieved by inactivation of other membrane-consuming pathways and a plasma membrane-like molecular signature of the compartment in these highly specialised heart cells.


Assuntos
Drosophila melanogaster , Endossomos , Animais , Membrana Celular/metabolismo , Drosophila melanogaster/metabolismo , Endocitose , Endossomos/metabolismo , Valvas Cardíacas/metabolismo , Transporte Proteico , Proteínas rab de Ligação ao GTP/metabolismo
18.
Nat Commun ; 13(1): 6127, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36253374

RESUMO

Clathrin-mediated endocytosis (CME) requires energy input from actin polymerization in mechanically challenging conditions. The roles of actin in CME are poorly understood due to inadequate knowledge of actin organization at clathrin-coated structures (CCSs). Using platinum replica electron microscopy of mammalian cells, we show that Arp2/3 complex-dependent branched actin networks, which often emerge from microtubule tips, assemble along the CCS perimeter, lack interaction with the apical clathrin lattice, and have barbed ends oriented toward the CCS. This structure is hardly compatible with the widely held "apical pulling" model describing actin functions in CME. Arp2/3 complex inhibition or epsin knockout produce large flat non-dynamic CCSs, which split into invaginating subdomains upon recovery from Arp2/3 inhibition. Moreover, epsin localization to CCSs depends on Arp2/3 activity. We propose an "edge pushing" model for CME, wherein branched actin polymerization promotes severing and invagination of flat CCSs in an epsin-dependent manner by pushing at the CCS boundary, thus releasing forces opposing the intrinsic curvature of clathrin lattices.


Assuntos
Actinas , Platina , Complexo 2-3 de Proteínas Relacionadas à Actina , Animais , Clatrina , Vesículas Revestidas por Clatrina , Endocitose , Mamíferos , Polimerização
19.
ACS Appl Mater Interfaces ; 14(41): 46850-46856, 2022 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-36198114

RESUMO

Micron-sized magnetic particles (M-MPs) have low toxicity, strong magnetic signals, and long-term retention capability, which are significant advantages for their application in biomedical imaging. Unfortunately, M-MPs are only internalized by few cell types, such as macrophages and phagocytes, and because of this lack of active intracellular delivery, their applications are restricted. The emergence of self-assembled virus-like particles (VLPs) offers a viable approach to drive M-MPs into cells, although the specific mechanism has not been revealed. In this study, we investigated in detail the intracellular pathway of M-MPs mediated by VLPs using a fluorescence co-localization method. The results indicated that the intracellular movement of M-MPs was consistent with the virus infection pathway, specifically caveolae-dependent endocytosis, transportation through microtubules, and accumulation in the endoplasmic reticulum. This study provides experimental support for the active transport of M-MPs into other cell types, thereby further extending their applications.


Assuntos
Endocitose , Viroses , Humanos , Retículo Endoplasmático , Microtúbulos , Fenômenos Magnéticos
20.
Cell Commun Signal ; 20(1): 161, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-36258231

RESUMO

The existence of multiple endocytic pathways is well known, and their exact biological effects in tumors have been intensively investigated. Endocytosis can affect the connection between tumor cells and determine the fate of tumor cells. Many relationships between endocytosis and tumor cells have been elucidated, but the mechanism of endocytosis between different types of cells in tumors needs to be explored in greater depth. Endocytic receptors sense the environment and are induced by specific ligands to trigger communication between tumor and immune cells. Crosstalk in the tumor microenvironment can occur through direct contact between cell adhesion molecules or indirectly through exosomes. So a better understanding of the endocytic pathways that control cell adhesion molecules and function is expected to lead to new candidates for cancer treatment. In additional, tumor-derived exosomes may changes immune cell function, which may be a key role for tumors to evade immune detection and response. The overall understanding of exosomes through endocytosis is also expected to bring new candidates for therapeutic regulation of tumor immune microenvironment. In this case, endocytic pathways coordinate cell adhesion molecules and exosomes and can be used as targets in the tumor immune microenvironment for cancer treatment. Video Abstract.


Assuntos
Exossomos , Neoplasias , Humanos , Microambiente Tumoral , Ligantes , Comunicação Celular , Exossomos/metabolismo , Endocitose , Neoplasias/metabolismo , Moléculas de Adesão Celular/metabolismo
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