Role of MTs & Motors in Podosome Function and Dynamics

This research direction currently includes two projects:

  1. The Role of Kinesin KIF1C in Podosome Regulation
    Extracellular matrix (ECM) degradation and remodeling is an essential component of tissue rearrangement, which occurs during development, tissue regeneration, and disease. In most cases, the ECM is changed by specific organelles, called podosomes, which are composed of an actin-based protrusion and adhesive ring. Podosomes are regulated by microtubules (MTs): we study the mechanisms and significance of this regulation in vascular smooth muscle cells. Vascular smooth muscle cells develop podosomes in order to migrate through ECM during angiogenesis and atherosclerosis progression. KIF1C is a kinesin motor, which has been shown to be is essential for podosome formation. In collaboration with Anne Straube's lab at the University of Warwick, we study the mechanisms whereby KIF1C activity is facilitated by podosome-inducing signaling. Our data indicate that MT-associated proteins CLASPs (CLIP-associated proteins) are indispensable for KIF1C-dependent transport (Journal of Cell Science 2014).
     
  2. CLASP-dependent MT Network Morphology
    For proper ECM remodeling, podosomes must be very dynamic and localize properly to the cell surface. We found that MTs are responsible for both spacial and temporal regulation of podosomes. Now, we are studying the role of MT-associated proteins in building a specialized MT network, which defines podosome positioning in vascular smooth muscle cells.
  • [Project 1] A7r5 rat aortic smooth muscle cells transfected with constituvely active Src to induce podosome formation at the cell periphery. In this image, bright actin puncta highlight the dense actin-core of the podosome. Phospho-Src (Tyr416) is shown in red, actin is shown in green (Phalloidin).
  • [Project 2] Image of an A7r5 cell, which has been depleted of CLASPs. In the absence of MT-stabilizing CLASP proteins, the MT network is less dense and disorganized. MTs are shown in red, the nucleus is shown in blue (DAPI).