We thank Nathan Belliveau, Maja Bialecka-Fornal, Justin Bois, Soichi Hirokawa, Jaspar Landman, Manuel Razo-Mejia, Muir Morrison, and Shyam Saladi for useful advice and discussion. We thank Don Court for strain XTL298 and Samantha Miller for strain MJF641. This work was supported by the National Institutes of Health DP1 OD000217 (Director’s Pioneer Award), R01 GM085286, GM084211-A1 , GM118043-01, and La Fondation Pierre Gilles de Gennes.