Slogging through Mud: Isoform Expression and Function

Abstract: The conserved protein Mud/NuMA/Lin-5 (flies, vertebrates, worms) has long been implicated in the orientation of cell division. Together with Dynein, Mud acts to produce a pulling force that reels astral microtubules, and therefore the metaphase spindle, into alignment. This force is anchored by another conserved factor, Pins/LGN/GPR1-2 (flies, vertebrates, worms), in most cell types examined. We and others have found that multiple isoforms of Mud do not include the Pins-binding domain. Mud is less well-studied outside of spindle orientation, but is implicated in diverse processes, including migration of the oocyte nucleus and spindle cohesion at meiosis II. We are currently investigating the expression and function of Mud isoforms, and in particular whether they participate in Mud function outside of spindle orientation.