Examining the Role of Phosphorylation in Receptor Localization and Chemotaxis in D. discoideum

Abstract

Phosphorylation of the C-terminus of cAR1 is thought to provide a role in the ability of cells to adapt to cAMP and respond to spatial gradients that span several orders of magnitude. It has been demonstrated that phosphorylation of cAR1 residues 299, 302, 303, and 304 regulate the affinity of the receptor for cAMP (Caterina 1995). I hypothesized that the phosphorylation status of the receptors allow them to respond to a wide dynamic range of cAMP concentrations and helps regulate the adaptation and de-adaptation of cellular responses to external cAMP. My work suggests that the phosphorylation state of the receptor contributes to the polarized redistribution of receptors and helps the cells chemotax in gradients with dramatically different mean concentrations. Understanding how these receptors polarize is of fundamental importance since they are critical for cAMP-mediated responses and the ability of a cell to sense concentration gradients of vastly different slopes and mean concentrations.