Figure 13.

γ-TuC organization and function in fission yeast. Schematic view that attempts to reconcile the phenotypic consequences of deletion of noncore γ-TuC components gfh1p, mod21p, and/or alp16p (i.e., reduced interphase microtubule nucleation) with our inability to detect a significant pool of large γ-TuCs on sucrose gradients. In this view, the fission yeast γ-TuC may exist as two populations: a small, abundant, but weakly active complex lacking noncore components (A); and a larger, much less abundant, but much more active complex containing noncore components, including a subcomplex of gfh1p and mod21p (B). In wild-type cells, both types of complexes could contribute to total microtubule nucleation.