September 5, 2014

It is so nice to have a friend who truly complements you…someone similar to you, but different enough to pick up the slack of your own shortcomings. Today’s image is from a paper about the Laverne and Shirley partnership of Ena/VASP and mDia2. 

Crawling cells extend finger-like filopodia to probe the environment for cues and to establish adhesion of the cell to the substrate. Filopodia are composed of parallel bundles of actin that are quickly dynamic. Countless actin regulators affect filopodia formation, some of which have seemingly similar functions. The Enabled (Ena)/VASP and Diaphanous 2 (mDia2) proteins are both actin polymerases, but as a recent paper by Barzik and colleagues describes, they support filopodia formation in distinct, non-redundant ways. By using mouse embryonic fibroblasts lacking both Ena/VASP and mDia2, Barzik and colleagues found that filopodia formed using either Ena/VASP or mDia2 alone differed in number, actin filament organization, lifetime, and other parameters. Filopodia generated using mDia2 alone were not able to initiate integrin-dependent adhesion and lamellipodial protrusions. The image above shows a cell with both mDia2 (red) and Ena/VASP (green), with the two proteins colocalizing on a subset of filopodia (arrows).

Barzik, M., McClain, L., Gupton, S., & Gertler, F. (2014). Ena/VASP regulates mDia2-initiated filopodial length, dynamics, and function Molecular Biology of the Cell, 25 (17), 2604-2619 DOI: 10.1091/mbc.E14-02-0712