Studying the contribution of coiled-coil domains to the phase separation of proteins

Membraneless organelles can form via liquid-liquid phase separation (LLPS), driven by multivalent interactions between proteins. Our previous simulation studies show coiled-coil (CC) domains can mediate multivalent interactions and drive protein LLPS. However, the role of CC domains in natural protein LLPS remains underexplored. A recent study identified that a fragment of human pericentrin, PCNT(854-1960), can undergo LLPS to form a functional centrosome. Importantly, this fragment is predicted to contain many CC domains. We hypothesize that CC domains facilitate the apparent LLPS behavior of PCNT. We present improved computational tools, including sequence-based interaction predictors and molecular simulations models, that utilize physics-based force fields that recapitulate natural CC interactions. We also present results that identify regions of PCNT(854-1960) which are necessary for its self-assembly, via a yeast microscopy platform. Preliminary results suggest that PCNT self-assembly might depend on interactions mediated by C-terminal CC domains. As CC domains are prevalent in membraneless organelles other than the centrosome, this work might be useful in understanding LLPS propensity of other CC proteins.