1
|
Li P, Li Y, Wang CC, Xia LG. Comparative transcriptomics reveals common and strain-specific responses of human macrophages to infection with Mycobacterium tuberculosis and Mycobacterium bovis BCG. Microb Pathog 2024; 189:106593. [PMID: 38387847 DOI: 10.1016/j.micpath.2024.106593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
Mycobacterium tuberculosis (MTB) and Mycobacterium bovis (M. bovis) are closely related pathogenic mycobacteria known to cause chronic pulmonary infections in both humans and animals. Despite sharing nearly identical genomes and virulence factors, these two bacteria display variations in host tropism, epidemiology, and clinical presentations. M. bovis Bacillus Calmette-Guérin (BCG) is an attenuated strain of M. bovis commonly utilized as a vaccine for tuberculosis (TB). Nevertheless, the molecular underpinnings of these distinctions and the intricacies of host-pathogen interactions remain areas of ongoing research. In this study, a comparative transcriptomic analysis was conducted on human leukemia macrophages (THP-1) infected with either MTB H37Rv or M. bovis BCG (Tokyo strain) to elucidate common and strain-specific responses at the transcriptional level. RNA sequencing was utilized to characterize the transcriptomes of human primary macrophages infected with MTB or BCG at 6 and 24 h post-infection. The findings indicate that both MTB and BCG induce substantial and dynamic alterations in the transcriptomes of THP-1, with a notable overlap in the quantity and extent of differentially expressed genes (DEGs). Moreover, gene ontology (GO) enrichment analysis unveiled shared pathways related to immune response, cytokine signaling, and apoptosis. The immune response of macrophages to bacterial infections at 6 h exhibited significantly greater intensity compared to that at 24 h. Furthermore, distinct gene sets displaying notable variances between MTB and BCG infections were identified. The profound impact of MTB infection on macrophage gene expression, particularly within the initial 6 h, was evident. Additionally, downregulation of pathways such as Focal adhesion, Rap1 signaling pathway, and Regulation of actin cytoskeleton was observed. The pathways associated with inflammation reactions and cell apoptosis exhibited significant differences, with BCG triggering macrophage apoptosis and MTB enhancing the survival of intracellular bacteria. Our findings reveal that MTB and BCG provoke similar yet distinct transcriptional responses in human macrophages, indicating variations in their pathogenesis and ability to adapt to host environments. These results offer novel insights into the molecular mechanisms governing host-pathogen interactions and may contribute to a deeper understanding of TB pathogenesis.
Collapse
Affiliation(s)
- Pei Li
- Division of Gastrointestinal Surgery, Department of General Surgery, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, Guangdong, China; Systematic Immunology of Tuberculosis, National Clinical Research Center for Infectious Disease, Shenzhen Third People's Hospital, Shenzhen, China
| | - Yang Li
- Division of Gastrointestinal Surgery, Department of General Surgery, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, Guangdong, China
| | - Cun Chuan Wang
- Division of Gastrointestinal Surgery, Department of General Surgery, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, Guangdong, China
| | - Li Gang Xia
- Division of Gastrointestinal Surgery, Department of General Surgery, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen 518020, Guangdong, China.
| |
Collapse
|
2
|
aVASP boosts protrusive activity of macroendocytic cups and drives phagosome rocketing after internalization. Eur J Cell Biol 2022; 101:151200. [DOI: 10.1016/j.ejcb.2022.151200] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 12/29/2022] Open
|
3
|
Kloc M, Uosef A, Villagran M, Zdanowski R, Kubiak JZ, Wosik J, Ghobrial RM. RhoA- and Actin-Dependent Functions of Macrophages from the Rodent Cardiac Transplantation Model Perspective -Timing Is the Essence. BIOLOGY 2021; 10:biology10020070. [PMID: 33498417 PMCID: PMC7909416 DOI: 10.3390/biology10020070] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/12/2021] [Accepted: 01/18/2021] [Indexed: 12/12/2022]
Abstract
Simple Summary The functions of animal and human cells depend on the actin cytoskeleton and its regulating protein called the RhoA. The actin cytoskeleton and RhoA also regulate the response of the immune cells such as macrophages to the microbial invasion and/or the presence of a non-self, such as a transplanted organ. The immune response against transplant occurs in several steps. The early step occurring within days post-transplantation is called the acute rejection and the late step, occurring months to years post-transplantation, is called the chronic rejection. In clinical transplantation, acute rejection is easily manageable by the anti-rejection drugs. However, there is no cure for chronic rejection, which is caused by the macrophages entering the transplant and promoting blockage of its blood vessels and destruction of tissue. We discuss here how the inhibition of the RhoA and actin cytoskeleton polymerization in the macrophages, either by genetic interference or pharmacologically, prevents macrophage entry into the transplanted organ and prevents chronic rejection, and also how it affects the anti-microbial function of the macrophages. We also focus on the importance of timing of the macrophage functions in chronic rejection and how the circadian rhythm may affect the anti-chronic rejection and anti-microbial therapies. Abstract The small GTPase RhoA, and its down-stream effector ROCK kinase, and the interacting Rac1 and mTORC2 pathways, are the principal regulators of the actin cytoskeleton and actin-related functions in all eukaryotic cells, including the immune cells. As such, they also regulate the phenotypes and functions of macrophages in the immune response and beyond. Here, we review the results of our and other’s studies on the role of the actin and RhoA pathway in shaping the macrophage functions in general and macrophage immune response during the development of chronic (long term) rejection of allografts in the rodent cardiac transplantation model. We focus on the importance of timing of the macrophage functions in chronic rejection and how the circadian rhythm may affect the anti-chronic rejection therapies.
Collapse
Affiliation(s)
- Malgorzata Kloc
- The Houston Methodist Research Institute, Houston, TX 77030, USA; (A.U.); (R.M.G.)
- Department of Surgery, The Houston Methodist Hospital, Houston, TX 77030, USA
- M.D. Anderson Cancer Center, Department of Genetics, The University of Texas, Houston, TX 77030, USA
- Correspondence:
| | - Ahmed Uosef
- The Houston Methodist Research Institute, Houston, TX 77030, USA; (A.U.); (R.M.G.)
- Department of Surgery, The Houston Methodist Hospital, Houston, TX 77030, USA
| | - Martha Villagran
- Electrical and Computer Engineering Department, University of Houston, Houston, TX 77204, USA; (M.V.); (J.W.)
- Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA
| | - Robert Zdanowski
- Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine (WIM), 04-141 Warsaw, Poland;
| | - Jacek Z. Kubiak
- Department of Regenerative Medicine and Cell Biology, Military Institute of Hygiene and Epidemiology (WIHE), 01-163 Warsaw, Poland;
- Cell Cycle Group, CNRS, Faculty of Medicine, Institute of Genetics and Development of Rennes, University of Rennes, UMR, 6290 Rennes, France
| | - Jarek Wosik
- Electrical and Computer Engineering Department, University of Houston, Houston, TX 77204, USA; (M.V.); (J.W.)
- Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA
| | - Rafik M. Ghobrial
- The Houston Methodist Research Institute, Houston, TX 77030, USA; (A.U.); (R.M.G.)
- Department of Surgery, The Houston Methodist Hospital, Houston, TX 77030, USA
| |
Collapse
|
4
|
Transcriptomic analysis of early stages of intestinal regeneration in Holothuria glaberrima. Sci Rep 2021; 11:346. [PMID: 33431961 PMCID: PMC7801731 DOI: 10.1038/s41598-020-79436-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 12/04/2020] [Indexed: 01/29/2023] Open
Abstract
Echinoderms comprise a group of animals with impressive regenerative capabilities. They can replace complex internal organs following injury or autotomy. In holothurians or sea cucumbers, cellular processes of intestinal regeneration have been extensively studied. The molecular machinery behind this faculty, however, remains to be understood. Here we assembled and annotated a de novo transcriptome using RNA-seq data consisting of regenerating and non-regenerating intestinal tissues from the sea cucumber Holothuria glaberrima. Comparisons of differential expression were made using the mesentery as a reference against 24 h and 3 days regenerating intestine, revealing a large number of differentially expressed transcripts. Gene ontology and pathway enrichment analysis showed evidence of increasing transcriptional activity. Further analysis of transcripts associated with transcription factors revealed diverse expression patterns with mechanisms involving developmental and cancer-related activity that could be related to the regenerative process. Our study demonstrates the broad and diversified gene expression profile during the early stages of the process using the mesentery as the focal point of intestinal regeneration. It also establishes the genes that are the most important candidates in the cellular processes that underlie regenerative responses.
Collapse
|
5
|
Kloc M, Uosef A, Kubiak JZ, Ghobrial RM. Role of Macrophages and RhoA Pathway in Atherosclerosis. Int J Mol Sci 2020; 22:ijms22010216. [PMID: 33379334 PMCID: PMC7796231 DOI: 10.3390/ijms22010216] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 12/20/2020] [Accepted: 12/24/2020] [Indexed: 12/11/2022] Open
Abstract
The development, progression, or stabilization of the atherosclerotic plaque depends on the pro-inflammatory and anti-inflammatory macrophages. The influx of the macrophages and the regulation of macrophage phenotype, inflammatory or anti-inflammatory, are controlled by the small GTPase RhoA and its downstream effectors. Therefore, macrophages and the components of the RhoA pathway are attractive targets for anti-atherosclerotic therapies, which would inhibit macrophage influx and inflammatory phenotype, maintain an anti-inflammatory environment, and promote tissue remodeling and repair. Here, we discuss the recent findings on the role of macrophages and RhoA pathway in the atherosclerotic plaque formation and resolution and the novel therapeutic approaches.
Collapse
Affiliation(s)
- Malgorzata Kloc
- Houston Methodist Research Institute, Houston, TX 77030, USA; (A.U.); (R.M.G.)
- Department of Surgery, Houston Methodist Hospital, Houston, TX 77030, USA
- M.D. Anderson Cancer Center, Department of Genetics, University of Texas, Houston, TX 77030, USA
- Correspondence:
| | - Ahmed Uosef
- Houston Methodist Research Institute, Houston, TX 77030, USA; (A.U.); (R.M.G.)
- Department of Surgery, Houston Methodist Hospital, Houston, TX 77030, USA
| | - Jacek Z. Kubiak
- Department of Regenerative Medicine and Cell Biology, Military Institute of Hygiene and Epidemiology (WIHE), 01-001 Warsaw, Poland;
- Cell Cycle Group, Institute of Genetics and Development of Rennes (IGDR), Faculty of Medicine, Univ Rennes, CNRS, UMR 6290, 35000 Rennes, France
| | - Rafik Mark Ghobrial
- Houston Methodist Research Institute, Houston, TX 77030, USA; (A.U.); (R.M.G.)
- Department of Surgery, Houston Methodist Hospital, Houston, TX 77030, USA
| |
Collapse
|
6
|
Keller S, Berghoff K, Kress H. Phagosomal transport depends strongly on phagosome size. Sci Rep 2017; 7:17068. [PMID: 29213131 PMCID: PMC5719076 DOI: 10.1038/s41598-017-17183-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/21/2017] [Indexed: 02/06/2023] Open
Abstract
Macrophages internalize pathogens for intracellular degradation. An important part of this process is the phagosomal transport from the cell periphery to the perinuclear region. Biochemical factors are known to influence the fate of phagosomes. Here, we show that the size of phagosomes also has a strong influence on their transport. We found that large phagosomes are transported persistently to the nucleus, whereas small phagosomes show strong bidirectional transport. We show that dynein motors play a larger role in the transport of large phagosomes, whereas actin filament-based motility plays a larger role in the transport of small phagosomes. Furthermore, we investigated the spatial distribution of dyneins and microtubules around phagosomes and hypothesize that dynein and microtubule density differences between the nucleus-facing side of phagosomes and the opposite side could explain part of the observed transport characteristics. Our findings suggest that a size-dependent cellular sorting mechanism might exist that supports macrophages in their immunological roles.
Collapse
Affiliation(s)
- S Keller
- Department of Physics, University of Bayreuth, Universitaetsstrasse 30, D-95440, Bayreuth, Germany.
| | - K Berghoff
- Department of Physics, University of Bayreuth, Universitaetsstrasse 30, D-95440, Bayreuth, Germany
| | - H Kress
- Department of Physics, University of Bayreuth, Universitaetsstrasse 30, D-95440, Bayreuth, Germany
| |
Collapse
|
7
|
Actoclampin (+)-end-tracking motors: How the pursuit of profilin's role(s) in actin-based motility twice led to the discovery of how cells crawl. Biophys Chem 2015; 209:41-55. [PMID: 26720287 DOI: 10.1016/j.bpc.2015.10.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/05/2015] [Indexed: 11/21/2022]
Abstract
The path to the discovery of the actoclampins began with efforts to define profilin's role in actin-based pathogen and endosome rocketing. That research identified a set of FPPPP-containing cargo proteins and FPPPP-binding proteins that are consistently stationed within the polymerization zone during episodes of active motility. The very same biophysical clues that forced us to abandon Brownian Ratchet models guided us to the Actoclampin Hypothesis, which asserts that every propulsive filament possesses a (+)-end-tracking motor that generates the forces cells need to crawl. Each actoclampin motor is a multi-arm oligomeric complex, employing one arm to recruit/deliver Profilin•Actin•ATP to a growth-site located at the (+)-end of the lagging subfilament, while a second arm maintains an affinity-modulated binding interaction with the extreme (+)-end of the other subfilament. The alternating actions of these arms define a true molecular motor, the processivity of which explains why propelling filaments maintain full possession of their cargo. The Actoclampin Hypothesis also suggests how the energetics of tracker interactions with the (+)-end determines whether a given actoclampin is a passive (low force-producing) or active (high force-producing) motor, the latter requiring the Gibbs free energy of ATP hydrolysis. Another aim of this review is to acknowledge an earlier notional model that emerged from efforts to comprehend profilin's pivotal role(s) in actin-based cell motility.
Collapse
|
8
|
Wang CL, Shaw BD. F-actin localization dynamics during appressorium formation in Colletotrichum graminicola. Mycologia 2015; 108:506-14. [PMID: 26297784 DOI: 10.3852/15-068] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 07/17/2015] [Indexed: 11/10/2022]
Abstract
Appressoria are essential penetration structures for many phytopathogenic fungi. Here F-actin localization dynamics were documented during appressorium formation in vitro and in planta in Colletotrichum graminicola Four discernible stages of dynamic F-actin distribution occurring in a programmed order were documented from differentiation of appressoria to formation of penetration pores: (stage A) from germ tube enlargement to complete expansion of the appressorium; (stage S) septation occurs; (stage L) a long period of low F-actin activity; (stage P) the penetration pore forms. The F-actin subcellular localization corresponded to each stage. A distinct redistribution of actin cables occurred at the transition from stage A to stage S. The in planta assays revealed that F-actin also assembled in invasive hyphae and that actin cables might play an essential role for penetration-peg development. The F-actin localization distribution may be used as a subcellular marker to define the developmental stages during appressorium formation.
Collapse
Affiliation(s)
- Chih-Li Wang
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas, and Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas
| |
Collapse
|
9
|
Khaitlina SY. Intracellular transport based on actin polymerization. BIOCHEMISTRY (MOSCOW) 2014; 79:917-27. [DOI: 10.1134/s0006297914090089] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
10
|
Dewerchin HL, Desmarets LM, Noppe Y, Nauwynck HJ. Myosins 1 and 6, myosin light chain kinase, actin and microtubules cooperate during antibody-mediated internalisation and trafficking of membrane-expressed viral antigens in feline infectious peritonitis virus infected monocytes. Vet Res 2014; 45:17. [PMID: 24517254 PMCID: PMC3937040 DOI: 10.1186/1297-9716-45-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 01/29/2014] [Indexed: 12/20/2022] Open
Abstract
Monocytes infected with feline infectious peritonitis virus, a coronavirus, express viral proteins in their plasma membranes. Upon binding of antibodies, these proteins are quickly internalised through a new clathrin- and caveolae-independent internalisation pathway. By doing so, the infected monocytes can escape antibody-dependent cell lysis. In the present study, we investigated which kinases and cytoskeletal proteins are of importance during internalisation and subsequent intracellular transport. The experiments showed that myosin light chain kinase (MLCK) and myosin 1 are crucial for the initiation of the internalisation. With co-localisation stainings, it was found that MLCK and myosin 1 co-localise with antigens even before internalisation started. Myosin 6 co-localised with the internalising complexes during passage through the cortical actin, were it might play a role in moving or disintegrating actin filaments, to overcome the actin barrier. One minute after internalisation started, vesicles had passed the cortical actin, co-localised with microtubules and association with myosin 6 was lost. The vesicles were further transported over the microtubules and accumulated at the microtubule organising centre after 10 to 30 min. Intracellular trafficking over microtubules was mediated by MLCK, myosin 1 and a small actin tail. Since inhibiting MLCK with ML-7 was so efficient in blocking the internalisation pathway, this target can be used for the development of a new treatment for FIPV.
Collapse
Affiliation(s)
| | | | | | - Hans J Nauwynck
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
| |
Collapse
|
11
|
Plattner H. Membrane Trafficking in Protozoa. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 280:79-184. [DOI: 10.1016/s1937-6448(10)80003-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
12
|
Liebl D, Griffiths G. Transient assembly of F-actin by phagosomes delays phagosome fusion with lysosomes in cargo-overloaded macrophages. J Cell Sci 2009; 122:2935-45. [PMID: 19638408 DOI: 10.1242/jcs.048355] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dynamic remodelling of the cortical actin cytoskeleton is required for phagocytic uptake of pathogens and other particles by macrophages. Actin can also be nucleated de novo on membranes of nascent phagosomes, a process that can stimulate or inhibit phagosome fusion with lysosomes. Recently, phagosomes were shown to polymerize actin in transient pulses, called actin ;flashing', whose function remains unexplained. Here, we investigated phagosomal actin dynamics in live macrophages expressing actin tagged with green fluorescent protein (GFP). We show that only immature phagosomes can transiently induce assembly of actin coat, which forms a barrier preventing phagosome-lysosome docking and fusion. The capacity of phagosomes to assemble actin is enhanced in cells exposed to increased phagocytic load, which also exhibit a delay in phagosome maturation. Parallel analysis indicated that polymerization of actin on macropinosomes also induces compression and propulsion. We show that dynamic interactions between membrane elastic tension and compression forces of polymerizing actin can also lead to macropinosome constriction and scission - a process that is obstructed on rigid phagosomes. We hypothesize that the rate of individual phagosome maturation, as well as the biogenesis and remodelling of macropinosomes, can be regulated by the extent and manner of actin assembly on their membrane.
Collapse
Affiliation(s)
- David Liebl
- Cell Biology and Biophysics Unit, EMBL Heidelberg, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
| | | |
Collapse
|
13
|
Actin dynamics and Rho GTPases regulate the size and formation of parasitophorous vacuoles containing Coxiella burnetii. Infect Immun 2009; 77:4609-20. [PMID: 19635823 DOI: 10.1128/iai.00301-09] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Q fever is a disease caused by Coxiella burnetii. In the host cell, this pathogen generates a large parasitophorous vacuole (PV) with lysosomal characteristics. Here we show that F-actin not only is recruited to but also is involved in the formation of the typical PV. Treatment of infected cells with F-actin-depolymerizing agents alters PV development. The small PVs formed in latrunculin B-treated cells were loaded with transferrin and Lysotracker and labeled with an antibody against cathepsin D, suggesting that latrunculin B did not affect vacuole cargo and its lysosomal characteristics. Nevertheless, the vacuoles were unable to fuse with latex bead phagosomes. It is known that actin dynamics are regulated by the Rho family GTPases. To assess the role of these GTPases in PV formation, infected cells were transfected with pEGFP expressing wild-type and mutant Rac1, Cdc42, and RhoA proteins. Rac1 did not show significant PV association. In contrast, PVs were decorated by both the wild types and constitutively active mutants of Cdc42 and RhoA. This association was inhibited by treatment of infected cells with chloramphenicol, suggesting a role for bacterial protein synthesis in the recruitment of these proteins. Interestingly, a decrease in vacuole size was observed in cells expressing dominant-negative RhoA; however, these small vacuoles accumulated transferrin, Lysotracker, and DQ-BSA. In summary, these results suggest that actin, likely modulated by the GTPases RhoA and Cdc42 and by bacterial proteins, is involved in the formation of the typical PV.
Collapse
|
14
|
Galletta BJ, Cooper JA. Actin and endocytosis: mechanisms and phylogeny. Curr Opin Cell Biol 2009; 21:20-7. [PMID: 19186047 DOI: 10.1016/j.ceb.2009.01.006] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 01/05/2009] [Accepted: 01/06/2009] [Indexed: 11/29/2022]
Abstract
The regulated assembly of actin filament networks is a crucial part of endocytosis, with crucial temporal and spatial relationships between proteins of the endocytic and actin assembly machinery. Of particular importance has been a wealth of studies in budding and fission yeast. Cell biology approaches, combined with molecular genetics, have begun to uncover the complexity of the regulation of actin dynamics during the endocytic process. In a wide range of organisms, clathrin-mediated endocytosis appears to be linked to Arp2/3-mediated actin assembly. The conservation of the components, across a wide range eukaryotic species, suggests that the partnership between endocytosis and actin may be evolutionarily ancient.
Collapse
Affiliation(s)
- Brian J Galletta
- Department of Cell Biology, Washington University Medical School, St Louis, MO, USA
| | | |
Collapse
|
15
|
Vincent C, Maridonneau-Parini I, Le Clainche C, Gounon P, Labrousse A. Activation of p61Hck triggers WASp- and Arp2/3-dependent actin-comet tail biogenesis and accelerates lysosomes. J Biol Chem 2007; 282:19565-74. [PMID: 17500055 DOI: 10.1074/jbc.m701501200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Secretory lysosomes exist in few cell types, but various mechanisms are involved to ensure their mobilization within the cytoplasm. In phagocytes, lysosome exocytosis is a regulated phenomenon at least in part under the control of the phagocyte-specific and lysosome-associated Src-kinase p61Hck (hematopoietic cell kinase). We show here that p61Hck activation triggered polymerization of actin at the membrane of lysosomes, which resulted in F-actin structures similar to comet tails observed on endocytic vesicles. We correlated this actin-comet biogenesis to a 35% acceleration of p61Hck-lysosomes in cells, which was dependent on actin polymerization and required an intact microtubular network. It was possible to initiate the formation of actin tails on p61Hck-positive lysosomes and on p61Hck-associated latex beads incubated in human phagocyte cytosolic extracts. The in vitro reconstitution on beads indicated that other lysosomal proteins were dispensable in this mechanism. The de novo actin polymerization process was functionally dependent on the kinase activity of Hck, WASp, the Arp2/3 complex, and Cdc42 but not Rac or Rho. Thus, we identified p61Hck as the first lysosomal protein able to recruit the molecular machinery responsible for actin tail formation. Altogether, our results suggest a new mechanism for lysosome motility involving p61Hck, actin-comet tail biogenesis, and the microtubule network.
Collapse
Affiliation(s)
- Claire Vincent
- Institut de Pharmacologie et de Biologie Structurale, CNRS UMR5089, 31077 Toulouse Cedex 04, France
| | | | | | | | | |
Collapse
|
16
|
Abstract
For genome multiplication hepadnaviruses use the transcriptional machinery of the cell that is found within the nucleus. Thus the viral genome has to be transported through the cytoplasm and nuclear pore. The intracytosolic translocation is facilitated by the viral capsid that surrounds the genome and that interacts with cellular microtubules. The subsequent passage through the nuclear pore complexes (NPC) is mediated by the nuclear transport receptors importin α and β. Importin α binds to the C-terminus of the capsid protein that comprises a nuclear localization signal (NLS). The exposure of the NLS is regulated and depends upon genome maturation and/or phosphorylation of the capsid protein. As for other karyophilic cargos using this pathway importin α interacts with importin β that facilitates docking of the import complex to the NPC and the passage through the pore. Being a unique strategy, the import of the viral capsid is incomplete in that it becomes arrested inside the nuclear basket, which is a cage-like structure on the karyoplasmic face of the NPC. Presumably only this compartment provides the factors that are required for capsid disassembly and genome release that is restricted to those capsids comprising a mature viral DNA genome.
Collapse
Affiliation(s)
- Michael Kann
- CNRS-REGER (UMR 5097), Bâtiment 3A, Université Bordeaux 2, 146 rue Leo Saignat, F-33076 Bordeaux Cedex, France.
| | | | | |
Collapse
|
17
|
Abstract
The cellular functions of the actin cytoskeleton require precise regulation of both the initiation of actin polymerization and the organization of the resulting filaments. The actin-related protein-2/3 (ARP2/3) complex is a central player in this regulation. A decade of study has begun to shed light on the molecular mechanisms by which this powerful machine controls the polymerization, organization and recycling of actin-filament networks, both in vitro and in the living cell.
Collapse
Affiliation(s)
- Erin D Goley
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | | |
Collapse
|
18
|
Fehrenbacher KL, Boldogh IR, Pon LA. A role for Jsn1p in recruiting the Arp2/3 complex to mitochondria in budding yeast. Mol Biol Cell 2005; 16:5094-102. [PMID: 16107558 PMCID: PMC1266410 DOI: 10.1091/mbc.e05-06-0590] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Although the Arp2/3 complex localizes to the leading edge of motile cells, endocytic structures, and mitochondria in budding yeast, the mechanism for targeting the Arp2/3 complex to different regions in the cell is not well understood. We find that Jsn1p, a member of the PUF family of proteins, facilitates association of Arp2/3 complex to yeast mitochondria. Jsn1p localizes to punctate structures that align along mitochondria, cofractionates with a mitochondrial marker protein during subcellular fractionation, and is both protease sensitive and carbonate extractable in isolated mitochondria. Thus, Jsn1p is a peripheral membrane protein that is associated with the outer leaflet of the mitochondrial outer membrane. Jsn1p colocalized and coimmunoprecipitated with mitochondria-associated Arc18p-GFP, and purified Arp2/3 complex bound to isolated TAP-tagged Jsn1p. Moreover, deletion of JSN1 reduces the amount of Arc18p-GFP that colocalizes and is recovered with mitochondria twofold, and jsn1Delta cells exhibited defects in mitochondrial morphology and motility similar to those observed in Arp2/3 complex mutants. Thus, Jsn1p has physical interactions with mitochondria-associated Arp2/3 complex and contributes to physical and functional association of the Arp2/3 complex with mitochondria.
Collapse
Affiliation(s)
- Kammy L Fehrenbacher
- Department of Anatomy and Cell Biology, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
| | | | | |
Collapse
|
19
|
Boldogh IR, Fehrenbacher KL, Yang HC, Pon LA. Mitochondrial movement and inheritance in budding yeast. Gene 2005; 354:28-36. [PMID: 15979253 DOI: 10.1016/j.gene.2005.03.049] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 03/23/2005] [Indexed: 10/25/2022]
Abstract
Mitochondria are essential organelles that perform fundamental cellular functions including aerobic energy mobilization, fatty acid oxidation, amino acid metabolism, heme biosynthesis and apoptosis. Mitochondria cannot be synthesized de novo. Therefore, the inheritance of this organelle is an essential part of the cell cycle; that is, daughter cells that do not inherit mitochondria will not survive. The budding yeast, Saccharomyces cerevisiae, is a facultative aerobe that can tolerate mitochondrial mutations that would be lethal in other organisms. Therefore, yeast has been used extensively to study inheritance and segregation of mitochondria. As a result, much of what we know regarding mitochondrial inheritance has been uncovered using yeast as a model system. Here, we describe the latest developments in mitochondrial motility and inheritance.
Collapse
Affiliation(s)
- Istvan R Boldogh
- Department of Anatomy and Cell Biology, Columbia University P&S 12-425, 630 West 168th Street, New York, NY 10032, USA
| | | | | | | |
Collapse
|
20
|
Balter A, Tang JX. Hydrodynamic stability of helical growth at low Reynolds number. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:051912. [PMID: 16089576 DOI: 10.1103/physreve.71.051912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2004] [Indexed: 05/03/2023]
Abstract
A cylindrical object growing at a low Reynolds number can spontaneously develop a helical shape. We have studied this phenomenon numerically, and our results may shed some light on the spontaneous formation of helical tails of a dense protein network observed in experiments on actin based motility. We also identify an unstable critical pitch angle which separates helices that straighten into rods from helices that flatten into planar curves as they grow. At the critical angle the pitch angle remains constant, whereas both helical diameter and pitch increase with the helical contour length.
Collapse
Affiliation(s)
- Ariel Balter
- Department of Physics, Indiana University, Bloomington, IN 47405, USA
| | | |
Collapse
|
21
|
Guiney DG, Lesnick M. Targeting of the actin cytoskeleton during infection by Salmonella strains. Clin Immunol 2005; 114:248-55. [PMID: 15721835 DOI: 10.1016/j.clim.2004.07.014] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Accepted: 07/22/2004] [Indexed: 10/26/2022]
Abstract
Many bacterial pathogens produce virulence factors that alter the host cell cytoskeleton to promote infection. Salmonella strains target cellular actin in a carefully orchestrated series of interactions that promote bacterial uptake into host cells and the subsequent proliferation and intercellular spread of the organisms. The Salmonella Pathogenicity Island 1 (SPI1) locus encodes a type III protein secretion system (TTSS) that translocates effector proteins into epithelial cells to promote bacterial invasion through actin cytoskeletal rearrangements. SPI1 effectors interact directly with actin and also alter the cytoskeleton through activation of the regulatory proteins, Cdc42 and Rac, to produce membrane ruffles that engulf the bacteria. SPI1 also restores normal cellular actin dynamics through the action of another effector, SptP. A second TTSS, Salmonella Pathogenecity Island 2 (SPI2), translocates effectors that promote intracellular survival and growth, accompanied by focal actin polymerization around the Salmonella-containing vacuole (SCV). A number of Salmonella strains also carry the spv virulence locus, encoding an ADP-ribosyl transferase, the SpvB protein, which acts later during intracellular infection to depolymerize the actin cytoskeleton. SpvB produces a cytotoxic effect on infected host cells leading to apoptosis. The SpvB effect appears to promote intracellular infection and may facilitate cell-to-cell spread of the organism, thereby enhancing virulence.
Collapse
Affiliation(s)
- Donald G Guiney
- Department of Medicine 0640, UCSD School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0640, USA.
| | | |
Collapse
|
22
|
Baluska F, Hlavacka A, Volkmann D, Menzel D. Getting connected: actin-based cell-to-cell channels in plants and animals. Trends Cell Biol 2005; 14:404-8. [PMID: 15308205 DOI: 10.1016/j.tcb.2004.07.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It has been known for more than one hundred years that plant cells are interconnected by cytoplasmic channels called plasmodesmata. This supracellularity was generally considered to be an exotic feature of walled plants containing immobile cells that are firmly enclosed within robust walls. Unexpectedly, intercellular channels in mobile animal cells have been discovered recently. These are extremely dynamic and sensitive to mechanical stress, which causes their rapid breakage and retraction. Both plasmodesmata and nanotubular cell-to-cell channels are supported by the actin cytoskeleton and exclude microtubules. In this article, we discuss the relevance of cell-to-cell channels not only for intercellular communication but also for the development and morphogenesis of multicellular organisms. We also suggest possible parallels between the cell-to-cell transport of endosomes and intracellular pathogens.
Collapse
Affiliation(s)
- Frantisek Baluska
- Institute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany.
| | | | | | | |
Collapse
|
23
|
Hosein RE, Williams SA, Gavin RH. Directed motility of phagosomes inTetrahymena thermophila requires actin and Myo1p, a novel unconventional myosin. ACTA ACUST UNITED AC 2005; 61:49-60. [PMID: 15810016 DOI: 10.1002/cm.20065] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The phagosome cycle was investigated in Tetrahymena thermophila, which had internalized fluorescent latex beads. Confocal microscopy of cells from a GFP-actin strain revealed actin filaments that extended 3-5 mum from the periphery of fluorescent phagosomes. In GFP-actin cells and in wild-type cells, motility of fluorescent phagosomes was directed from the oral cavity to the posterior end of the cell. Although 60% of fluorescent phagosomes in the MYO1-knockout strain were motile, movement of phagosomes was not directed toward the posterior end of the cell and was random. Forty percent of fluorescent phagosomes in knockout cells were non-motile in contrast to only 20% non-motile phagosomes in wild-type cells. The increased incidence of non-motile phagosomes in the knockout strain could reflect absence of Myo1p as a motor. Another myosin or other molecular motors could power random movement of phagosomes in the MYO1-knockout strain. In latrunculin-treated GFP-actin cells, movement of fluorescent phagosomes was random. Average velocity of random movement of fluorescent phagosomes in the knockout strain and in latrunculin-treated cells was statistically the same as the average velocity (2.0 +/- 1.9 microm/min) of phagosomes in GFP-actin cells. These findings are an indication that dynamic actin and Myo1p are required for directed motility of phagosomes.
Collapse
Affiliation(s)
- Roland E Hosein
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, New York 11210, USA
| | | | | |
Collapse
|
24
|
Huckaba TM, Gay AC, Pantalena LF, Yang HC, Pon LA. Live cell imaging of the assembly, disassembly, and actin cable-dependent movement of endosomes and actin patches in the budding yeast, Saccharomyces cerevisiae. ACTA ACUST UNITED AC 2004; 167:519-30. [PMID: 15534003 PMCID: PMC2172478 DOI: 10.1083/jcb.200404173] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Using FM4-64 to label endosomes and Abp1p-GFP or Sac6p-GFP to label actin patches, we find that (1) endosomes colocalize with actin patches as they assemble at the bud cortex; (2) endosomes colocalize with actin patches as they undergo linear, retrograde movement from buds toward mother cells; and (3) actin patches interact with and disassemble at FM4-64–labeled internal compartments. We also show that retrograde flow of actin cables mediates retrograde actin patch movement. An Arp2/3 complex mutation decreases the frequency of cortical, nonlinear actin patch movements, but has no effect on the velocity of linear, retrograde actin patch movement. Rather, linear actin patch movement occurs at the same velocity and direction as the movement of actin cables. Moreover, actin patches require actin cables for retrograde movements and colocalize with actin cables as they undergo retrograde movement. Our studies support a mechanism whereby actin cables serve as “conveyor belts” for retrograde movement and delivery of actin patches/endosomes to FM4-64–labeled internal compartments.
Collapse
Affiliation(s)
- Thomas M Huckaba
- Department of Anatomy and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | | | | | | | | |
Collapse
|
25
|
Yam PT, Theriot JA. Repeated cycles of rapid actin assembly and disassembly on epithelial cell phagosomes. Mol Biol Cell 2004; 15:5647-58. [PMID: 15456901 PMCID: PMC532043 DOI: 10.1091/mbc.e04-06-0509] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 09/17/2004] [Accepted: 09/20/2004] [Indexed: 11/11/2022] Open
Abstract
We have found that early in infection of the intracellular pathogen Listeria monocytogenes in Madin-Darby canine kidney epithelial cells expressing actin conjugated to green fluorescent protein, F-actin rapidly assembles (approximately 25 s) and disassembles (approximately 30 s) around the bacteria, a phenomenon we call flashing. L. monocytogenes strains unable to perform actin-based motility or unable to escape the phagosome were capable of flashing, suggesting that the actin assembly occurs on the phagosome membrane. Cycles of actin assembly and disassembly could occur repeatedly on the same phagosome. Indirect immunofluorescence showed that most bacteria were fully internalized when flashing occurred, suggesting that actin flashing does not represent phagocytosis. Escherichia coli expressing invA, a gene product from Yersinia pseudotuberculosis that mediates cellular invasion, also induced flashing. Furthermore, polystyrene beads coated with E-cadherin or transferrin also induced flashing after internalization. This suggests that flashing occurs downstream of several distinct molecular entry mechanisms and may be a general consequence of internalization of large objects by epithelial cells.
Collapse
Affiliation(s)
- Patricia T Yam
- Department of Biochemistry, Stanford University School of Medicine, Stanford CA 94305, USA
| | | |
Collapse
|
26
|
Abstract
Cells such as macrophages take up pathogens into specialized membrane organelles (phagosomes) that fuse with other organelles, including lysosomes, in a process termed maturation. The fully matured phagolysosome is a low-pH, hydrolase-rich killing device that some pathogens can bypass. One might expect that phagosomes containing a given type of particle that entered cells simultaneously via the same receptor would behave the same, at least in a single cell. Surprisingly, however, recent data show that phagosomes formed via the same receptors can find themselves in different chemical states even within the same macrophage. Here, I argue that each phagosome is an individual entity whose behaviour depends on a finite number of stable equilibrium states in its membrane signalling networks.
Collapse
Affiliation(s)
- Gareth Griffiths
- EMBL, Meyerhofstrasse 1, Postfach 102209, 69117 Heidelberg, Germany.
| |
Collapse
|
27
|
Abstract
PURPOSE OF REVIEW This review focuses on recent developments in understanding the roles and regulation of the cytoskeleton in the function of leukocytes. RECENT FINDINGS New studies have shed light on the regulation and dynamics of actin and microtubules in leukocytes relevant both to cell motility generally and to immune function specifically. The roles of cytoskeletal dynamics in processes such as cell activation, cell migration, and phagocytosis are being elucidated. Dramatic progress has been made recently in understanding the mechanisms of leukocyte directional sensing, polarization, and chemotaxis. SUMMARY Leukocytes need to be activated, polarize, change shape, move, or phagocytose in response to their environment. Leukocytes accomplish these processes by remodeling their cytoskeleton, the active musculoskeletal system of the cell that is not just the ultimate effector of motile responses but is also a dynamic framework for subcellular organization and regional signaling. Active areas of research include the direct and indirect reciprocal interactions between the cytoskeleton and the membrane and among cytoskeletal elements. The pervasive and multi-layered roles played by small GTPases of the Rho family and phosphoinositides in leukocyte function are also becoming clearer.
Collapse
Affiliation(s)
- Gabriel Fenteany
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607-7061, USA.
| | | |
Collapse
|
28
|
Kjeken R, Egeberg M, Habermann A, Kuehnel M, Peyron P, Floetenmeyer M, Walther P, Jahraus A, Defacque H, Kuznetsov SA, Griffiths G. Fusion between phagosomes, early and late endosomes: a role for actin in fusion between late, but not early endocytic organelles. Mol Biol Cell 2003; 15:345-58. [PMID: 14617814 PMCID: PMC307552 DOI: 10.1091/mbc.e03-05-0334] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Actin is implicated in membrane fusion, but the precise mechanisms remain unclear. We showed earlier that membrane organelles catalyze the de novo assembly of F-actin that then facilitates the fusion between latex bead phagosomes and a mixture of early and late endocytic organelles. Here, we correlated the polymerization and organization of F-actin with phagosome and endocytic organelle fusion processes in vitro by using biochemistry and light and electron microscopy. When membrane organelles and cytosol were incubated at 37 degrees C with ATP, cytosolic actin polymerized rapidly and became organized into bundles and networks adjacent to membrane organelles. By 30-min incubation, a gel-like state was formed with little further polymerization of actin thereafter. Also during this time, the bulk of in vitro fusion events occurred between phagosomes/endocytic organelles. The fusion between latex bead phagosomes and late endocytic organelles, or between late endocytic organelles themselves was facilitated by actin, but we failed to detect any effect of perturbing F-actin polymerization on early endosome fusion. Consistent with this, late endosomes, like phagosomes, could nucleate F-actin, whereas early endosomes could not. We propose that actin assembled by phagosomes or late endocytic organelles can provide tracks for fusion-partner organelles to move vectorially toward them, via membrane-bound myosins, to facilitate fusion.
Collapse
Affiliation(s)
- Rune Kjeken
- European Molecular Biology Laboratory, D-69117 Heidelberg, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Hestvik ALK, Hmama Z, Av-Gay Y. Kinome analysis of host response to mycobacterial infection: a novel technique in proteomics. Infect Immun 2003; 71:5514-22. [PMID: 14500469 PMCID: PMC201077 DOI: 10.1128/iai.71.10.5514-5522.2003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An array of mammalian phospho-specific antibodies was used to screen for a host response upon mycobacterial infection, reflected as changes in host protein phosphorylation. Changes in the phosphorylation state of 31 known signaling molecules were tracked after infection with live or heat killed Mycobacterium bovis BCG or after incubation with the mycobacterial cell wall component lipoarabinomannan (LAM). Mycobacterial infection triggers a signaling cascade leading to activation of stress-activated protein kinase and its subsequent downstream target, c-Jun. Mycobacteria were also shown to inhibit the activation of protein kinase C epsilon and to induce phosphorylation of proteins not yet known to be involved in mycobacterial infection, such as the cytoskeletal protein alpha-adducin, glycogen synthase kinase 3beta, and a receptor subunit involved in regulation of intracellular Ca(2+) levels. The mycobacterial cell wall component LAM has been identified as a trigger for some of these modulation events.
Collapse
Affiliation(s)
- Anne Lise K Hestvik
- Department of Medicine, Division of Infectious Diseases, University of British Columbia. Vancouver, BC V5Z 3J5, Canada
| | | | | |
Collapse
|
30
|
Rutenberg AD, Richardson AJ, Montgomery CJ. Diffusion of asymmetric swimmers. PHYSICAL REVIEW LETTERS 2003; 91:080601. [PMID: 14525230 DOI: 10.1103/physrevlett.91.080601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2003] [Indexed: 05/24/2023]
Abstract
Particles moving along curved trajectories will diffuse if the curvature fluctuates sufficiently in either magnitude or orientation. We consider particles moving at a constant speed with either a fixed or a Gaussian distributed magnitude of curvature. At small speeds the diffusivity is independent of the speed. At larger particle speeds, the diffusivity depends on the speed through a novel exponent. We apply our results to intracellular transport of vesicles. In sharp contrast to thermal diffusion, the effective diffusivity increases with vesicle size and so may provide an effective means of intracellular transport.
Collapse
Affiliation(s)
- Andrew D Rutenberg
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada B3H 3J5
| | | | | |
Collapse
|
31
|
Abstract
Phagocytosis is the process that cells have evolved to internalise large particles such as mineral debris, which they store, or apoptotic cells and pathogens, which they have the capacity to kill and degrade. However, several important pathogens can suppress these killing functions and survive and multiply within phagosomes, causing disease. Recent advances in phagosome biology have been made possible largely by a model system that uses inert latex beads. The ability to purify latex bead-containing phagosomes has opened the door to allow comprehensive biochemical analyses and functional assays to study the molecular mechanisms governing phagosome function. These approaches have led to unique insights directly relevant for the understanding of the biology of intracellular pathogens and the ways by which they subvert their hosts.
Collapse
Affiliation(s)
- Michel Desjardins
- Département de Pathologie et Biologie Cellulaire, Université de Montréal, CP 6128, Succ. centre ville, H3C 3J7, Montreal, Canada.
| | | |
Collapse
|
32
|
Southwick FS, Li W, Zhang F, Zeile WL, Purich DL. Actin-based endosome and phagosome rocketing in macrophages: activation by the secretagogue antagonists lanthanum and zinc. CELL MOTILITY AND THE CYTOSKELETON 2003; 54:41-55. [PMID: 12451594 DOI: 10.1002/cm.10083] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Although motile endocytic vesicles form actin-rich rocket tails [Merrifield et al., 1999: Nature Cell Biol 1:72-74], the mechanism of intracellular organelle locomotion remains poorly understood. We now demonstrate that bone marrow macrophages treated with lanthanum and zinc ions, well-known secretagogue antagonists, reliably exhibit vesicle motility. This treatment results in accentuated membrane ruffling and the formation of phagosomes and early endosomes that move rapidly through the cytoplasm by assembling actin filament rocket tails. Protein-specific immunolocalization demonstrated the presence of Arp2/3 complex in the polymerization zone and throughout the actin-rich tail, whereas N-WASP was most abundant in the polymerization zone. Although Arp2/3 and N-WASP play essential roles in nucleating filament assembly, other processes (i.e., elongation and filament cross-linking) are required to produce forces needed for motility. Efficient elongation was found to require zyxin, VASP, and profilin, proteins that interact by means of their ABM-1 and ABM-2 proline-rich motifs. The functional significance of these motifs was demonstrated by inhibition of vesicle motility by the motif-specific ABM-1 and ABM-2 analogues. Furthermore, lanthanum/zinc treatment also facilitated the early onset of actin-based vaccinia motility, a process that also utilizes Arp2/3 and N-WASP for nucleation and the zyxin-VASP-profilin complex for efficient elongation. Although earlier studies using cell extracts clouded the role of oligoproline sequences in activating the polymerization zone, our studies emphasize the importance of evaluating motility in living cells.
Collapse
Affiliation(s)
- Frederick S Southwick
- Division of Infectious Diseases, Department of Medicine, University of Florida College of Medicine, Gainesville 32610-0277, USA.
| | | | | | | | | |
Collapse
|
33
|
Plattner H, Kissmehl R. Molecular Aspects of Membrane Trafficking in Paramecium. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 232:185-216. [PMID: 14711119 DOI: 10.1016/s0074-7696(03)32005-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Results achieved in the molecular biology of Paramecium have shed new light on its elaborate membrane trafficking system. Paramecium disposes not only of the standard routes (endoplasmic reticulum --> Golgi --> lysosomes or secretory vesicles; endo- and phagosomes --> lysosomes/digesting vacuoles), but also of some unique features, e.g. and elaborate phagocytic route with the cytoproct and membrane recycling to the cytopharynx, as well as the osmoregulatory system with multiple membrane fusion sites. Exocytosis sites for trichocysts (dense-core secretory vesicles), parasomal sacs (coated pits), and terminal cisternae (early endosomes) display additional regularly arranged predetermined fusion/fission sites, which now can be discussed on a molecular basis. Considering the regular, repetitive arrangements of membrane components, availability of mutants for complementation studies, sensitivity to gene silencing, and so on, Paramecium continues to be a valuable model system for analyzing membrane interactions. This review intends to set a new baseline for ongoing work along these lines.
Collapse
Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
| | | |
Collapse
|