Formation of the IGF:IGFBP3:ALS complex

IGFBP3 binds IGF I or IGF II via the conserved N terminus and C terminus of IGFBP 3. IGFBP3 also binds ALS via the C terminal portion of IGFBP3. The interaction is dependent on the glycosylation of ALS.<br>IGFBP3, which binds most IGF in the body, is enriched in follicular fluid and found in many other tissues. IGFBP3 may be cleaved by plasmin, thrombin, Prostate specific Antigen (PSA, KLK3), Matrix Metalloprotease-1 (MMP1), and Matrix Metalloprotease-2 (MMP2). IGFBP3 also binds extracellular matrix and binding lowers its affinity for IGFs. IGFBP3 stimulates the effects of IGFs.<br>

IGFBP3通过保留的N端和C端与IGF I或IGF II结合。IGFBP3亦可通过IGFBP3的C端部分与ALS结合。此相互作用依赖于ALS的糖基化。IGFBP3，作为体内大部分IGF的结合蛋白，在毛囊液中含量丰富，并存在于许多其他组织中。IGFBP3可被纤溶酶、凝血酶、前列腺特异性抗原（PSA，KLK3）、基质金属蛋白酶-1（MMP1）和基质金属蛋白酶-2（MMP2）所切割。IGFBP3亦与细胞外基质结合，且结合作用降低其对IGFs的亲和力。IGFBP3可激发IGFs的作用。