Integrating High Resolution Bioimaging Techniques to Unravel Spatio-Temporal Organization of Podosomes

Abstract

Podosomes are highly dynamic adhesion structures which consist of a dense actin core surrounded by a ring of integrins and adaptor proteins (Fig. 1A), typically associated with focal adhesions (FAs). Interestingly, while it is well established that myosin mediated tension plays an essential role in regulating adaptor protein recruitment to FAs, it is unknown whether similar mechanisms control podosome assembly. Here, by combining FRAP with Image Correlation Spectroscopy, we identify myosin-independent mechanisms that recruit adaptor proteins during podosome assembly (Fig. 1B). Moreover, we provide evidence that the cortical actin network creates the necessary tension eliciting the recruitment of adaptor proteins during podosome assembly. Combined with super-resolution STORM images of individual podosomes, our studies provide novel detailed insight into podosome spatio-temporal organization. A model integrating these results will be presented.Figure 1Organization and dynamics of podosome components in antigen-presenting cells. A) Podosomes are adhesion structures containing a dense actin core and a ring of vinculin, talin and other cytoskeletal components. B) Correlated fluoresence intensities of actin and cytoskeletal adaptor proteins at a single podosome in time.View Large Image | View Hi-Res Image | Download PowerPoint Slide