Transient Transfection Assays for Analysis of Signal Transduction in Renal Cells

Functional analysis of plasma-membrane receptors often involves the ectopic expression of receptor constructs in cultured cell lines followed by assay of the activation of cytosolic or nuclear signaling targets (1 ). Although in the simplest cases full-length receptors are expressed and subsequently activated by ligand binding, this is not always feasible or desirable. For example, it may not be possible to clone and/or express the full-length receptor. There are also cases in which the ligand is unknown. It may also be desirable to examine the function of only a portion of the receptor, or to put a receptor under the control of an unrelated ligand. In these cases, the development of assays for receptor function can involve the cloning of fusion constructs that express membrane-targeted chimeric-receptor proteins.