DIFFERENTIAL COUPLING OF CC CHEMOKINE RECEPTORS TO MULTIPLE HETEROTRIMERIC G-PROTEINS IN HUMAN INTERLEUKIN-2-ACTIVATED NATURAL-KILLER-CELLS

Using two different approaches, we have investigated the types of G pr oteins coupled to CC chemokine receptors. First, permeabilization of i nterleukin-2-activated natural killer (IANK) cells with streptolysin-O and introduction of anti-G protein antibodies inside these cells resu lted in the following. (1) Anti-G(s), anti-G(o), and anti-G(z) inhibit ed the migration of IANK cells in response to macrophage-inflammatory protein-1 alpha (MIP-1 alpha), monocyte chemoattractant protein-1 (MCP -1), or regulated on activation normal T cell expressed and secreted ( RANTES). (2) Anti-G(i) inhibited their migration in response to MCP-1 or RANTES but not in response to MIP-1 alpha. Second, incubation of IA NK cell membranes with anti-G protein antibodies before incubating wit h (gamma-S-35) GTP or (gamma-P-32) GTP, resulted in the following. (1) Anti-G(s), anti-G(o), or anti-G(z) inhibited GTP binding and GTPase a ctivity in the presence of MIP-1 alpha, MCP-1, or RANTES. (2) Anti-G(i ) inhibited GTP binding and GTPase activity in the presence of MCP-1 o r RANTES but not in the presence of MIP-1 alpha. The inhibitory effect of anti-G protein antibodies was reversed upon incubating these antib odies with their respective synthetic peptides before addition to IANK cell membranes. These results suggest that MCP-1 and RANTES receptors are promiscuously coupled to multiple G proteins in IANK cell membran es and that this coupling is different from MIP-1 alpha receptors, whi ch seem to be coupled to G(s), G(o), and G(z) but not to G(i). (C) 199 6 by The American Society of Hematology.