The mannose 6-phosphate/insulin-like growth factor II receptor is a nanomolar affinity receptor for glycosylated human leukemia inhibitory factor.
Comparison of the binding properties of non-glycosylated, glycosylated human leukemia inhibitory factor (LIF) and monoclonal antibodies (mAbs) directed at gp190/LIF-receptor beta subunit showed that most of the low affinity (nanomolar) receptors expressed by a variety of cell lines are not due to gp190. These receptors bind glycosylated LIF produced in Chinese hamster ovary cells (CHO LIF) (Kd = 6.9 nM) but not Escherichia coli-derived LIF or CHO LIF treated with endoglycosidase F. CHO LIF binding to these receptors is neither affected by anti-gp190 mAbs nor by anti-gp130 mAbs and is specifically inhibited by low concentrations of mannose 6-phosphate (Man-6-P) (IC50 = 40 microM), suggesting that they could be related to Man-6-P receptors. The identity of this LIF binding component with the Man-6-P/insulin-like growth factor-II receptor (Man-6-P/IGFII-R) was supported by several findings. (i) It has a molecular mass very similar to that of the Man-6-P/IGFII-R (270 kDa); (ii) the complex of LIF cross-linked to this receptor is immunoprecipitated by a polyclonal anti-Man-6-P/IGFII-R antibody; (iii) this antibody inhibits LIF and IGFII binding to the receptor with comparable efficiencies; (iv) soluble Man-6-P/IGFII-R purified from serum binds glycosylated LIF (Kd = 4.3 nM) but not E. coli LIF. The potential role of Man-6-P/IGFII-R in LIF processing and biological activity is discussed.
Blanchard
F
F
Groupe de Recherche Cytokines/Récepteurs/Transduction, Unité INSERM 463, France.
Raher
S
S
Duplomb
L
L
Vusio
P
P
Pitard
V
V
Taupin
J L
JL
Moreau
J F
JF
Hoflack
B
B
Minvielle
S
S
Jacques
Y
Y
Godard
A
A
D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D006224:Cricetinae; D017931:DNA Primers; D006031:Glycosylation; D006131:Growth Inhibitors / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D008222:Lymphokines / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism; D011485:Protein Binding; D017527:Receptor, IGF Type 2 / Q000097:blood / Q000302:isolation & purification / Q000378:metabolism*; D018121:Receptors, Cytokine / Q000378:metabolism*; D053606:Receptors, OSM-LIF; D011994:Recombinant Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D006131:Growth Inhibitors; D015850:Interleukin-6; C507837:LIF protein, human; C507840:LIFR protein, human; D053605:Leukemia Inhibitory Factor; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D008222:Lymphokines; D017527:Receptor, IGF Type 2; D018121:Receptors, Cytokine; D053606:Receptors, OSM-LIF; D011994:Recombinant Proteins; D008358:Mannose