Biochemical responses to chemoattractants in Dictyostelium: ligand-receptor interactions and downstream kinase activation.
Dictyostelium discoideum is one of the most facile eukaryotic systems for the study of chemotactic response to secreted chemical ligands. Dictyostelium grow as individual cells, using bacteria and fungi as primary nutrient sources; during growth, Dictyostelium moves directionally toward folate, a bacterial byproduct. Upon nutrient depletion Dictyostelium initiates a multicellular development program characterized by the production and secretion of cAMP. Cell surface receptors specifically recognize extracellular cAMP, which serves as both a morphogen to promote development and a chemoattractant to organize multicellularity. We discuss several approaches for the study of ligand-receptor interaction, with focus on affinity class determination and quantification of ligand binding sites (i.e., receptors) per cell. We further present examples for the application of biochemical assays to characterize the ligand-induced kinase activation of PI3K, GSK3, and ERK2.
Liao
Xin-Hua
XH
Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA.
Kimmel
Alan R
AR
D000818:Animals; D002630:Chemotactic Factors / Q000494:pharmacology*; D000242:Cyclic AMP / Q000494:pharmacology; D004023:Dictyostelium / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005492:Folic Acid / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D015800:Protozoan Proteins / Q000378:metabolism
D002630:Chemotactic Factors; D018129:Phosphatidylinositol Phosphates; D015800:Protozoan Proteins; D005492:Folic Acid; D000242:Cyclic AMP; D019950:Mitogen-Activated Protein Kinase 1; D038362:Glycogen Synthase Kinase 3; D019204:GTP-Binding Proteins