Figure 1.

Description of chimeric receptor chains. (A) The chimeric GM-CSF/IL-2 receptor consists of two chains, ββ and αγ, that bind human GM-CSF but generate an IL-2 signal through cytoplasmic domains derived from human IL-2Rβ and γ_c (4, 37). The chains associate noncovalently with the kinases Jak1 and Jak3, respectively (6–8, 40), each of which contains a C-terminal tyrosine kinase (TK) domain and six other conserved regions (JH2–7). (B) Derivatives of αγ containing an attached murine Jak3 molecule in the cytoplasmic domain (46), the PROX domain alone (αγ-PROX), or the C-terminal region of γ_c alone (37) (αγ-ΔPROX). (C) Amino acid sequence of the cytoplasmic domains of αγ-derived receptor chains beginning with the first cytoplasmic residue (19). Linker sequences are in bold type.