IL-8 single-chain homodimers and heterodimers: interactions with chemokine receptors CXCR1, CXCR2, and DARC.
Covalent single-chain dimers of the chemokine interleukin-8 (IL-8) have been designed to mimic the dimeric form of IL-8 in solution and facilitate the production of heterodimer variants of IL-8. Physical studies indicated that use of a simple peptide linker to join two subunits, while allowing receptor binding and activation, led to self-association of the tethered dimers. However, addition of a single disulfide crosslink between the tethered subunits prevented this multimer from forming, yielding a species of dimer molecular weight. Crosslinked single-chain dimers bind to both IL-8 neutrophil receptors CXCR1 and CXCR2 as well as to DARC, as does a double disulfide-linked dimer with no peptide linker. In addition, neutrophil response to these dimers as measured by chemotaxis or beta-glucuronidase release is similar to that elicited by wild-type IL-8, providing evidence that the dissociation of the dimeric species is not required for these biologically relevant activities. Finally, through construction of single-chain heterodimer mutants, we show that only the first subunit's ELR motif is the single-chain variants.
Leong
S R
SR
Department of Immunology, Genentech, Inc., South San Francisco, California 94080, USA.
Lowman
H B
HB
Liu
J
J
Shire
S
S
Deforge
L E
LE
Gillece-Castro
B L
BL
McDowell
R
R
Hébert
C A
CA
D015703:Antigens, CD / Q000378:metabolism*; D001704:Biopolymers; D016209:Interleukin-8 / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D011487:Protein Conformation; D018123:Receptors, Interleukin / Q000378:metabolism*; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B
D015703:Antigens, CD; D001704:Biopolymers; D016209:Interleukin-8; D018123:Receptors, Interleukin; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B