APC is a component of an organizing template for cortical microtubule networks.
A microtubule network on the basal cortex of polarized epithelial cells consists of non-centrosomal microtubules of mixed polarity. Here, we investigate the proteins that are involved in organizing this network, and we show that end-binding protein 1 (EB1), adenomatous polyposis coli protein (APC) and p150Glued - although considered to be microtubule plus-end-binding proteins - are localized along the entire length of microtubules within the network, and at T-junctions between microtubules. The network shows microtubule behaviours that arise from physical interactions between microtubules, including microtubule plus-end stabilization on the sides of other microtubules, and sliding of microtubule ends along other microtubules. APC also localizes to the basal cortex. Microtubules grew over and paused at APC puncta; an in vitro reconstituted microtubule network overlaid APC puncta; and microtubule network reconstitution was inhibited by function-blocking APC antibodies. Thus, APC is a component of a cortical template that guides microtubule network formation.
Reilein
Amy
A
Department of Molecular and Cellular Physiology, Beckman Center for Molecular and Genetic Medicine B121, 279 Campus Drive, Stanford University School of Medicine, Stanford, CA 94305-5435, USA.
Nelson
W James
WJ
D025601:Adenomatous Polyposis Coli Protein / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D016764:Cell Polarity / Q000502:physiology; D004285:Dogs; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D011485:Protein Binding; D014404:Tubulin / Q000378:metabolism
D025601:Adenomatous Polyposis Coli Protein; D000072159:Dynactin Complex; C405804:EB1 microtubule binding proteins; D008869:Microtubule-Associated Proteins; D014404:Tubulin