Dr. Tim Stearns: Stanford University in Stanford, Calif., Frank Lee and Carol Hall Professor of Biology and Department of Biology chair; and the professor of genetics at Stanford School of Medicine

Abstract: The centriole is one of the most highly conserved structures in eukaryotic cells, and is essential for forming a cilium, an important signaling organelle in most cells. Defects in cilium formation and function are the cause of a wide range of human disease conditions. Centrioles are composed of long-lived microtubules arranged in nine triplets, a configuration that is found only in centrioles. However, the contribution of triplet microtubules to mammalian centriole formation and stability is unknown. We have found that mutations in two little-studied members of the tubulin superfamily, delta-tubulin and epsilon-tubulin, result in centrioles that lack triplet microtubules and fail to undergo centriole maturation. These aberrant centrioles are formed de novo each cell cycle, but are unstable and do not persist to the next cell cycle, leading to a futile cycle of centriole formation and disintegration Thus, the conserved triplet microtubule structure of centrioles is necessary for inheritance of centrioles from one cell cycle to the next.

Refreshments will be served prior to the GDCB Seminar at 3:45 p.m.

Host: Moe Gupta