Article

Phagocytosis and cytokinesis: do cells use common tools to cut and to eat ? Highlights on common themes and differences.

CNRS, UMR 8104, Paris, France
Traffic (Impact Factor: 4.71). 01/2013; DOI: 10.1111/tra.12045
Source: PubMed

ABSTRACT Eukaryotic cells with specialized functions often use and adapt common molecular machineries. Recent findings have highlighted that actin polymerization, contractile activity and membrane remodelling with exocytosis of internal compartments are required both for successful phagocytosis, the internalization of particulate material, and for cytokinesis, the last step of cell division. Phagocytosis is induced by the triggering of specific cell surface receptors, which leads to membrane deformation, pseudopod extension and contraction to engulf particles. Cytokinesis relies on intense contractile activity and eventually leads to the physical scission of sister cells. In this review, shared features of signalling, cytoskeletal reorganization and vesicular trafficking used in both phagocytosis and cytokinesis will be described, but we will also highlight non-common mechanisms and questions that remain open in these dynamic areas of research.

1 Follower
 · 
89 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In many secretory cells actin and myosin are specifically recruited to the surface of secretory granules following their fusion with the plasma membrane. Actomyosin-dependent compression of fused granules is essential to promote active extrusion of cargo. Yet, little is known about molecular mechanisms regulating actin coat formation and contraction. Here we provide a detailed kinetic analysis of the molecules regulating actin coat contraction on fused lamellar bodies (LBs) in primary alveolar type II cells. We demonstrate that Rock1 and myosin light chain kinase (MLCK) translocate to fused LBs and activate myosin II on actin coats. Yet, myosin II activity is not sufficient for efficient actin coat contraction. In addition, cofilin-1 and α-actinin translocate to actin coats. Rock1-dependent, regulated actin depolymerisation by cofilin-1 in cooperation with actin crosslinking by α-actinin is essential for complete coat contraction. In summary, our data suggest a complementary role for regulated actin depolymerisation/crosslinking and myosin II activity to contract actin coats and drive secretion.
    Journal of Cell Science 01/2015; 128(6). DOI:10.1242/jcs.165571 · 5.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cited By (since 1996):3, Export Date: 18 October 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: The midbody remnant (MBR) that is generated after cytokinesis abscission has recently attracted a lot of attention, since it may have crucial consequences for cell differentiation and tumorigenesis in mammalian cells. In those cells, it has been reported that the MBR is either released into the extracellular medium, or retracted into one of the two daughter cells where it can be degraded by autophagy. Here, we describe a major alternative pathway in a variety of human and mouse immortalized/cancer and primary stem cells. Using correlative light/scanningEM microscopy and quantitative assays, we found that sequential abscissions on both sides of the midbody generate free MBRs, which are tightly associated to the cell surface through a Ca(++)/Mg(++)-dependent receptor. Surprisingly, MBRs move over the cell surface for several hours, before being eventually engulfed by an actin-dependent phagocytosis-like mechanism. Mathematical modelling combined to experiments further demonstrates that lysosomal activities fully account for clearance of MBRs after engulfment. This study changes our vision of how MBRs are inherited and degraded in mammalian cells, and suggests a mechanism by which MBRs might signal over long distances between cells.
    Journal of Cell Science 07/2014; 127(17). DOI:10.1242/jcs.154732 · 5.33 Impact Factor

Preview

Download
1 Download