CAREER: Signal Transduction of Eukaryotic Quorum Sensing

Cuny Hunter College, New York NY

Investigators

Abstract

The ability of mammalian cells to sense the density of the cells around them plays an important role in cellular growth control and differentiation. Without such ability a developing embryo would be unable to properly proportion its cells into different tissue types. Unfortunately, studying this phenomenon in mammals is difficult due to their complexity. Therefore, this project is designed to uncover and study the genetic regulation of cell density sensing by using the social ameoba Dictyostelium discoideum as a model. Dictyostelium cells display many of the characteristics of mammalian cells, including but not limited to motility, differentiation, development and cell to cell signaling. Thus, they present themselves as excellent models for mammalian cell behavior, especially cell density sensing. When starved, Dictyostelium cells will undergo a period of differentiation and development leading to the formation of a multicellular organism. However, this process will not begin unless there are sufficient numbers of starving cells to form a full sized organism. Therefore, these cells are able to sense the density of the starving cells around them and respond appropriately. This sensing is accomplished by secreting and responding to a protein called Conditioned Medium Factor (CMF). As more cells starve, the levels of CMF rise until they reach a threshold level, at which point the cells are able to initiate development. This project will delineate how CMF levels are sensed by cells and impact their decision to develop. By uncovering the function of CMF in Dictyostelium discoideum, a better understanding of cell density sensing in mammalian cells can be gained, and with it, a better understanding of its role in development. These experiments will be incorporated into teaching laboratories where undergraduate students will participate in hands-on experiments with Dictyostelium mutants and their characterization and manipulation. Hunter College has a large population of minority students who will participate in these laboratories.