Our latest BCMB Friday Seminar, held on 9 November 2012, was by Peter Devreotes , a BCMB faculty member. He spoke about his lab’s contribution to the field of cell migration. After a wonderful introduction by BCMB student Chris Mitchell, the seminar began with a historical overview of chemotaxis, which is an essential part of human development.
It was in the Devreotes lab where the observation was made that PIP3 has a greater concentration at the leading edge of a cell. This helped decipher the conundrum of how signal gradients activate pathways preferentially on one side of the cell, when receptors are evenly spaced around a cell. Another major contribution to the field from the Devreotes lab is the development of Dictyostelium as a model organism for studying cell migration. To this end, the Devreotes lab made the pioneering discoveries of the first G proteins and G protein-coupled receptors in this organism. In his seminar, Dr. Devreotes showed many fascinating movies of cells moving towards chemoattractants, and when labeled for any of the 27 known “front” proteins or the 7 known “back” proteins, you can see that the cells can sense the signal, become polarized, and move in the direction of the chemoattractant.
According to Dr. Devreotes, the most exciting work on the horizon for the field of cell migration is a systems biology understanding of this process. We now appreciate that cell migration is an important part of cell biology, and scientists have identified over a hundred important genes involved, but we have yet to put it all together into a comprehensive pathway. Dr. Devreotes described that this will require integrating many different kinds of experiments into one growing picture.
Some of the exciting new data that Dr. Devreotes presented in his seminar was based on TIRF microscopy, which allowed his lab to view waves of responses at the cell periphery in response to a chemoattractant. These waves, when viewed in t-stacks, can be categorized into two types of signals: those with intervals of about 10 seconds, and those with intervals of about 100 seconds. Furthermore, unstimulated cells appear to have oscillations that might contribute to their excitability, accounting for their rapid response once chemoattractant is introduced. When Dictyostelium are grown in a monolayer, waves of responses spiral out from the point of stimulation, and this correlates with translocation of the transcription factor, gtaC, into and out of the nucleus, possibly acting as a cellular pacemaker. These kinds of observations of spatiotemporal responses to dynamic signaling are what drives the Devreotes lab’s current research.
Dr. Devreotes is currently accepting BCMB rotation students, and promises interesting rotation projects within the topics described in today’s seminar. During Dr. Devreotes’ time as a professor, he has trained about fifty scientists, including advising 17 BCMB students for their PhD. Two of these trainees are now themselves BCMB faculty: Michael Caterina and Miho Iijima. Dr. Devreotes left a big mark on the BCMB program while he was the director. In 1990, he started the Policy Committee, before which time there were not a lot of written policies. He helped pioneer the rotation assignment system and the policy of having annual thesis committee meetings with official paperwork. With Dr. Devreotes as Director, the Cell Biology Department has more than doubled in its number of faculty, and Dr. Devreotes describes them as “a great group of people.”
After the seminar, Dr. Devreotes, BCMB students and faculty, and other guests enjoyed a reception of drinks and snacks outside the auditorium. I had the opportunity to chat with Dr. Devreotes in person, and when I asked him about his key to success, he says, “you have to do what you really really like to do. You have to want to know things – if you don’t, you shouldn’t be doing this. And then you have to work hard. And then you have to be lucky. But it starts with [thinking], ‘I’m doing this because I love nature.’ ” He gestures towards the outdoors, where the Baltimore trees are showing their fall colors. With excitement in his eyes, he exclaims, “just look around you!” It is this kind of curiosity-driven science that Dr. Devreotes values, and emphasized in today’s BCMB Friday Seminar.