Evolution of an ancient protein function involved in organized multicellularity in animals
Douglas P Anderson, Dustin S Whitney, Victor Hanson-Smith, Arielle Woznica, William Campodonico-Burnett, Brian F Volkman, Nicole King, Kenneth E PrehodaCorresponding Author, Joseph W ThorntonCorresponding Author
University of Oregon, United States; Medical College of Wisconsin, United States; Howard Hughes Medical Institute, University of California, Berkeley, United States; University of Chicago, United States
Published January 7, 2016
Cite as eLife 2016;5:e10147
The top image is a fluorescence micrograph of a dividing solitary choanoflagellate showing its DNA (blue) and flagella and mitotic spindle (green). A small choanoflagellate colony is shown below, with one of its cells dividing.
Source/Fonte: Ken Prehoda via ScienceDaily
Abstract
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.
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