Tunable Assembly of Protein‐Microdomains in Living Vertebrate Embryos

Subcellular events such as trafficking and signaling are regulated by self‐assembled protein complexes inside the cell. The ability to rapidly and reversibly manipulate these protein complexes would likely enhance studies of their mechanisms and their roles in biological function and disease manifestation. This paper reports that thermally responsive elastin‐like polypeptides (ELPs) linked to fluorescent proteins can regulate the self‐assembly and disassembly of protein microdomains within the individual cells of zebrafish embryos. By exploring a library of fluorescent ELP proteins, this report demonstrates that ELPs can coassemble different fluorescent proteins inside of embryos. By tuning ELP length and sequence, fluorescent protein microdomains can be assembled at different temperatures, in varying sizes, or for desired periods of time. For the first time in a multicellular living embryo, these studies demonstrate that temperature‐mediated ELP assembly can reversibly manipulate assembly of subcellular protein complexes, which may have applications in the study and manipulation of in vivo biological functions. A new temperature‐dependent strategy to modulate protein assembly in a vertebrate embryo is developed using a thermo‐responsive elastin‐like polypeptide (ELP). By tuning the ELP length and sequence, protein microdomains can be induced to assemble at different temperatures, in varying sizes, or for different time periods inside of zebrafish embryos.