A chimeric MIP-1alpha/RANTES protein demonstrates the use of different regions of the RANTES protein to bind and activate its receptors.
Human RANTES (CCL5) and MIP-1alpha (CCL3) bind and activate several CC chemokine receptors. RANTES is a high-affinity ligand for CCR1 and CCR5, and it binds CCR3 with moderate affinity and CCR4 with low affinity. MIP-1alpha has similar binding characteristics to RANTES except that it does not bind to CCR3. Here we have generated a chimera of human MIP-1alpha and RANTES, called MIP/RANTES, consisting of the eight amino terminal residues of MIP-1alpha preceding the CC motif, and the remainder of the sequence is RANTES. The chimera is able to induce chemotaxis of human monocytes. MIP/RANTES has >100-fold reduction in binding to CCR1 and does not bind to CCR3 but retains full, functional binding to CCR5. It has equivalent affinity for CCR5 to MIP-1alpha and RANTES, binding with an IC(50) of 1.12 nM, and is able to mobilize calcium and induce endocytosis of CCR5 in PBMC in a manner equi-potent to RANTES. It also retains the ability to inhibit R5 using HIV-1 strains. Therefore, we conclude that the amino terminus of RANTES is not involved in CCR5 binding, but it is essential for CCR1 and CCR3.
Blanpain
C
C
IRIBHN Université Libre de Bruxelles, Campus Erasme, Bruxelles, Belgium.
Buser
R
R
Power
C A
CA
Edgerton
M
M
Buchanan
C
C
Mack
M
M
Simmons
G
G
Clapham
P R
PR
Parmentier
M
M
Proudfoot
A E
AE
D000595:Amino Acid Sequence; D001667:Binding, Competitive; D020013:Calcium Signaling / Q000187:drug effects; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018946:Chemokine CCL5 / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism*; D002633:Chemotaxis / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects; D015497:HIV-1 / Q000502:physiology; D019402:Macrophage Inflammatory Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000187:drug effects; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D054389:Receptors, CCR1; D054398:Receptors, CCR4; D019713:Receptors, CCR5 / Q000378:metabolism*; D019707:Receptors, Chemokine / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000502:physiology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
C515300:CCR1 protein, human; C515354:CCR4 protein, human; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018946:Chemokine CCL5; D019402:Macrophage Inflammatory Proteins; C108335:RANTES, Met-; D054389:Receptors, CCR1; D054398:Receptors, CCR4; D019713:Receptors, CCR5; D019707:Receptors, Chemokine; D011993:Recombinant Fusion Proteins; C111989:aminooxypentane-RANTES