If you invited a protein to a party, it’d win your Twister tournament without a doubt. A protein is not just some static stick of cellular function, but can be a complicated structure that bends or twists in three dimensions and can interact with other domains (of itself or another protein). Today’s image is from a paper describing a thorough analysis of one domain on a Shroom protein.
Shroom (Shrm) proteins play important roles throughout development. Through their interaction with Rho kinase (Rock), Shroom proteins regulate the localization of the actin-myosin contractile network, which in turn affects cell and tissue shape. A recent paper describes a specific domain of Shrm, the SD2 domain, and its importance in the interaction between Shrm and Rock. In this paper, Mohan and colleagues present the structure of the SD2 domain and show the specific amino acid residues on the protein that are necessary for Shrm-Rock interaction, both in vertebrates and invertebrates. In the images above, mammalian cell cultures are treated with different Shrm SD2 constructs. Intact SD2 domains for both mouse (top) and fruit fly (middle) were able to constrict the cells expressing the construct (green cells). Without the SD2 domain (bottom), cells were unable to constrict.
Mohan, S., Rizaldy, R., Das, D., Bauer, R., Heroux, A., Trakselis, M., Hildebrand, J., & VanDemark, A. (2012). Structure of Shroom domain 2 reveals a three-segmented coiled-coil required for dimerization, Rock binding, and apical constriction Molecular Biology of the Cell, 23 (11), 2131-2142 DOI: 10.1091/mbc.E11-11-0937