Regulation of gene expression, growth, and cell survival by IL-4: Contribution of multiple signaling pathways

Abstract

Interleukin-4 is a cytokine produced by activated T cells, mast cells, and basophils that elicits many important biological responses [1] (see Tab 1). These responses range from the regulation of helper T cell differentiation [2] and the production of IgE [3] to the regulation of the adhesive properties of endothelial cells via VCAM-1[4]. In keeping with these diverse biological effects, high-affinity binding sites for IL-4 (Kd 20 to 300 pM) have been detected on many hematopoietic and non-hematopoietic cell types at levels ranging from 50 to 5000 sites per cell [5]. This review will focus on the discrete signal transduction pathways activated by the IL-4 receptor and the coordination of these individual pathways in the regulation of a final biological outcome.