Table 1.

Characteristics of individual IGFBPs.

Binding protein	C-terminus	Central linker domain	N-terminus
IGFBP-1	•IGF binding	•Phosphorylation sites	•IGF binding
	•Integrin binding
IGFBP-2	•IGF binding	•Heparin binding
	•Integrin binding
IGFBP-3	•IGF binding	•Heparin binding •Phosphorylation sites •N-glycosylation	•IGF binding •Insulin binding •Inhibitor of IR auto-phosphorylation •Inhibitor of mitogenesis
	•Cell binding/penetration (GAG domain)
	•Nuclear localization signal
	•Heparin binding
	•ALS (Acid labile subunit) binding
IGFBP-4	•IGF binding	•N-glycosylation	•IGF binding
IGFBP-5	•IGF binding	•ALS binding •Heparin binding •Phosphorylation sites	•IGF binding
	•Nuclear localization signal
	•Heparin binding
	•ALS binding
IGFBP-6	•Heparin binding	•N-glycosylation	•IGF binding
	•IGF-II binding
IGFBP-7		•Kazal-like domain •N-glycosylation	•Ig-like C2-type