Galphai generates multiple Pins activation states to link cortical polarity and spindle orientation in Drosophila neuroblasts.

ABSTRACT: Drosophila neuroblasts divide asymmetrically by aligning their mitotic spindle with cortical cell polarity to generate distinct sibling cell types. Neuroblasts asymmetrically localize Galphai, Pins, and Mud proteins; Pins/Galphai direct cortical polarity, whereas Mud is required for spindle orientation. It is currently unknown how Galphai-Pins-Mud binding is regulated to link cortical polarity with spindle orientation. Here, we show that Pins forms a "closed" state via intramolecular GoLoco-tetratricopeptide repeat (TPR) interactions, which regulate Mud binding. Biochemical, genetic, and live imaging experiments show that Galphai binds to the first of three Pins GoLoco motifs to recruit Pins to the apical cortex without "opening" Pins or recruiting Mud. However, Galphai and Mud bind cooper

SUBMITTER: Nipper RW 

PROVIDER: S-EPMC1964812 | biostudies-literature | 2007 Sep

REPOSITORIES: biostudies-literature