Calmodulin-regulated spectrin-associated protein 3
cytoplasm
Anchorage of microtubule minus ends to adherens junctions regulates epithelial cell-cell contacts.
Epithelial cells contain noncentrosomal microtubules (MTs), whose minus ends are oriented apically. In contrast with the well-known interactions of the minus ends with the centrosome, little is known about the termination site of the noncentrosomal minus ends. Here we show that a population of MT minus ends is anchored at the zonula adherens (ZA), the apical-most part of the cadherin-based adherens junction, via a protein that we have termed Nezha. We initially identified PLEKHA7 as a ZA component and subsequently detected Nezha as a partner for PLEKHA7. Nezha bound MTs at their minus ends and tethered them to the ZA. Furthermore, we found that a minus end-directed motor, KIFC3, was concentrated at the ZA in a PLEKHA7/Nezha/MT-dependent manner; and depletion of any of these proteins resulted in disorganization of the ZA. We propose that the PLEKHA7/Nezha/MT complex regulates the ZA integrity by recruiting KIFC3 to this junctional site.