Reconstitution of the transition from a lamellipodia- to filopodia-like actin network with purified proteins

Eur J Cell Biol. 2023 Oct 20;102(4):151367. doi: 10.1016/j.ejcb.2023.151367. Online ahead of print.ABSTRACTHow cells utilize complex mixtures of actin binding proteins to assemble and maintain functionally diverse actin filament networks with distinct architectures and dynamics within a common cytoplasm is a longstanding question in cell biology. A compelling example of complex and specialized actin structures in cells are filopodia which sense extracellular chemical and mechanical signals to help steer motile cells. Filopodia have distinct actin architecture, composed of long, parallel actin filaments bundled by fascin, which form finger-like membrane protrusions. Elongation of the parallel actin filaments in filopodia can be mediated by two processive actin filament elongation factors, formin and Ena/VASP, which localize to the tips of filopodia. There remains debate as to how the architecture of filopodia are generated, with one hypothesis proposing that filopodia are generated from the lamellipodia, which consists of densely packed, branched actin filaments nucleated by Arp2/3 complex and kept short by capping protein. It remains unclear if different actin filament elongation factors are necessary and sufficient to facilitate the emergence of filopodia with diverse characteristics from a highly dense network of short-branched capped filaments. To address this question, we combined bead motility and micropatterning biomimetic assays with multi-color Total Internal Reflecti...

Source: European Journal of Cell Biology - October 27, 2023 Category: Cytology Authors: Cristian Suarez Jonathan D Winkelman Alyssa J Harker Hannah J Ye Patrick M McCall Alisha N Morganthaler Margaret L Gardel David R Kovar Source Type: research