title: Spatiotemporal dynamics of actin-rich adhesion microdomains: influence of substrate flexibility.
abstract: In this study we analyse the formation and dynamics of specific actin-rich structures called podosomes. Podosomes are very dynamic punctual adhesion sites tightly linked to the actin cytoskeleton. Mechanical properties of substrates are emerging as important physical modulators of anchorage-dependent processes involved in the cellular response. We investigate the influence of substrate flexibility on the dynamic properties of podosomes. We used mouse NIH-3T3 fibroblasts, transfected with GFP-actin and cultured on polyacrylamide collagen-coated substrates of varying stiffness. Static and dynamic features of cell morphologies associated with an optical flow analysis of the dynamics of podosomes revealed that: (1) they have constant structural properties, i.e. their shape factor and width do not change with the substrate flexibility; (2) the lifespan of podosomes and mean minimum distance between them depend on the substrate flexibility; (3) there is a variation in the displacement speed of the rosette of podosomes. Moreover, the rosettes sometimes appear as periodically emergent F-actin structures, which suggests that a two-level self-organisation process may drive first, the formation of clusters of podosomes and second, the organisation of these clusters into oscillating rings. Such dynamic features give new perspectives regarding the potential function of podosomes as mechanosensory structures.
authors.affiliation: Equipe DynaCell, Laboratoire TIMC-IMAG, CNRS UMR5525, Institut de l'Ingénierie et de l'Information de Santé-Faculté de Médecine, 38706 La Tronche CEDEX, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Collin
authors.forename: Philippe
authors.initials: P
authors.lastname: Tracqui
authors.forename: Angélique
authors.initials: A
authors.lastname: Stephanou
authors.forename: Yves
authors.initials: Y
authors.lastname: Usson
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Clément-Lacroix
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Planus
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology*; D018929:Cell Culture Techniques / Q000295:instrumentation*; D002462:Cell Membrane / Q000378:metabolism*; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D041681:NIH 3T3 Cells / Q000187:drug effects; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000199:Actins; D019384:Nucleic Acid Synthesis Inhibitors; D011993:Recombinant Fusion Proteins; D015638:Cytochalasin D