Evolution of an ancient protein function involved in organized multicellularity in animals.
- Author(s): Anderson, Douglas P;
- Whitney, Dustin S;
- Hanson-Smith, Victor;
- Woznica, Arielle;
- Campodonico-Burnett, William;
- Volkman, Brian F;
- King, Nicole;
- Thornton, Joseph W;
- Prehoda, Kenneth E
- et al.
Published Web Locationhttps://doi.org/10.7554/elife.10147
To form and maintain organized tissues, multicellular organisms orient their mitotic spindles relative to neighboring cells. A molecular complex scaffolded by the GK protein-interaction domain (GKPID) mediates spindle orientation in diverse animal taxa by linking microtubule motor proteins to a marker protein on the cell cortex localized by external cues. Here we illuminate how this complex evolved and commandeered control of spindle orientation from a more ancient mechanism. The complex was assembled through a series of molecular exploitation events, one of which - the evolution of GKPID's capacity to bind the cortical marker protein - can be recapitulated by reintroducing a single historical substitution into the reconstructed ancestral GKPID. This change revealed and repurposed an ancient molecular surface that previously had a radically different function. We show how the physical simplicity of this binding interface enabled the evolution of a new protein function now essential to the biological complexity of many animals.