Dissecting Spatial and Temporal Sensing in Dictyostelium Chemotaxis Using a Wave Gradient Generator
External cues that dictate the direction of cell migration are likely dynamic during many biological processes such as embryonic development and wound healing. Until recently, how cells integrate spatial and temporal information to determine the direction of migration has remained elusive. In Dictyostelium discoideum, the chemoattractant cAMP that directs cell aggregation propagates as periodic waves. In light of the fact that any temporally evolving complex signals, in principle, can be expressed as a sum of sinusoidal functions with various frequencies, the Dictyostelium system serves as a minimal example, where the dynamic signal is in the simplest form of near sinusoidal wave with one dominant frequency. Here, we describe a method to emulate the traveling waves in a fluidics device. The text provides step-by-step instructions on the device setup and describes ways to analyze the acquired data. These include quantification of membrane translocation of fluorescently labeled proteins in individual Dictyostelium cells and estimation of exogenous cAMP profiles. The described approach has already helped decipher spatial and temporal aspects of chemotactic sensing in Dictyostelium. More specifically, it allowed one to discriminate the temporal and the spatial sensing aspects of directional sensing. With some modifications, one should be able to implement similar analysis in other cell types.
Key wordsChemotaxis Dictyostelium cAMP waves MFCS Gradient sensing Temporal-sensing
This work was supported by grants from the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research on Innovative Areas (23111506, 25111704) (to S.S.), JSPS Grant-in-Aid for Young Scientists (A) (22680024, 25710022) (to S.S.), JSPS Grant-in-Aid for Young Scientists (Start-up) and (B) (23870006, 25840069) (to A.N.), Japan Science and Technology Agency (JST) Precursory Research for Embryonic Science and Technology (PRESTO) (to S.S.), Platform for Dynamic Approaches to Living System from the Ministry of Education, Culture, Sports, Science and Technology, Japan, and in part by the Human Frontier Science Programme (RGY 70/2008) and JSPS Grant-in-Aid for Scientific Research on Innovative Areas (25103008) (to S.S.).