The Cytokine Receptor Family

Abstract

The cytokine receptors comprise an evolutionarily related group of molecules which fall into two distinct classes; namely the class I and class II cytokine receptors^79–81 (Figs. 5-9). Class I comprises the cellular receptors for many interleukine (IL), such as those that regulate hematopoiesis, e.g., IL-3⁸² IL-5, IL-11, granulocyte-macrophage colony stimulating factor (GM-CSF),^83,84 granulocyte-colony stimulating factor (G-CSF),^85,86 erythropoietin (EPO),^85,87 and thrombopoietin (TPO),^88,89 those that regulate lymphocyte production and function, e.g., IL-2,^90–92 IL-4,⁹³ IL-9,⁹⁴ IL-7, IL-12, IL-13, IL-14 and IL-15, and those that have more pleiotropic effects such as growth hormone (GH), prolactin (PRL), IL-6,⁹⁵ leukemia inhibitory factor (LIF),⁹⁶ ciliary neurotrophic factor (CNTF)⁹⁷ and Oncostatin M (OSM). The class II cytokine receptors include the receptors for interferon γ (IFNγ),⁹⁸ interferon α (IFNα)^99,100 and IL-10.¹⁰¹