Research

Microtubule organizing centers (MTOCs) are fundamentally important for segregating chromosomes during cell division, as well as organizing the interphase microtubule cytoskeleton. MTOCs organize microtubules (MT) by controlling nucleation. The morphology of MTOCs varies depending on the type of eukaryote; in metazoa the MTOC is the centrosome, whereas in yeast it is the Spindle Pole Body (SPB). Even though MTOCs are morphologically different cross-species, all eukaryotes utilize g-tubulin (Tub4p in yeast) to nucleate microtubules in vivo. g-tubulin is found in a 300kDa g-Tubulin Small Complex (g-TuSC), a heterotetramer with two copies of g-tubulin and one each of Spc98p/Dgrip91/Xgrip110 and Spc97p/Dgrip84/Xgrip109. In metazoa, g-TuSC is a repeating component within the larger g-Tubulin Ring Complex (g-TuRC). While both purified g-tubulin and the g-TuRC are potent MT nucleators, surprisingly nucleating activity for g-TuSC is barely detectable even though it is the only g-tubulin complex within the highly functional S. cerevisiae SPB. There is some evidence that g-TuSC forms larger complexes in yeast, as well as having capped MTs similar to g-TuRC capped MTs in higher eukaryotes.

I am interested in determining the relative orientations of Spc97p and Spc98p within the yeast g-TuSC and the structural implications for nucleation with binding partners, such as Spc110p and Spc72p using single particle Electron Microscopy (EM). In addition, I am interested in improving data processing schemes to tackle the inherent problems of solving heterogenous structures.

Publications

coming soon!!