The Secret (Mitotic) Life of Clathrin

The discovery of clathrin was a foundational event in membrane traffic research. Its identification as the major protein component of the coat that surrounds endocytic vesicles kickstarted the biochemical and molecular characterization of endocytosis. During this explosive period of cell biology, there was a parallel storyline involving clathrin which developed more slowly. It emerged that clathrin has an alternative function during mitosis, and that this function is unrelated to its membrane trafficking role. Clathrin forms part of a multiprotein complex that stabilizes microtubules of the mitotic spindle during the chromosome segregation events that occur during cell division. Due to this dual functionality, clathrin is sometimes referred to as a "moonlighting" protein. In this Perspective, we will take a look at this secret life of clathrin and examine how it carries out its mitotic function.