Insulin-like growth factor-binding protein 1-6 (IGFBP1-6)

The Insulin-like growth factor-binding proteins (IGFBP-1 to IGFBP-6) are a family of six high-affinity carrier proteins that regulate the bioavailability and activity of insulin-like growth factors (IGF-I and IGF-II) [1]. These proteins circulate in the blood and are present in the extracellular matrix, where they protect IGFs from degradation and transport them to specific tissues [2]. Beyond their role as passive carriers, IGFBPs can either inhibit or enhance IGF signaling by controlling the interaction between IGFs and the IGF-1 receptor [3]. Additionally, several IGFBPs exhibit IGF-independent actions, such as regulating cell proliferation, apoptosis, and migration through interactions with other cell surface receptors or by translocating to the nucleus [4]. Dysregulation of IGFBPs is implicated in various pathologies, including cancer, metabolic disorders, and growth-related conditions, making them significant targets for therapeutic intervention and diagnostic biomarkers [5]. In clinical practice, recombinant IGFBP-3 is used in combination with IGF-I (Mecasermin rinfabate) to treat severe primary IGF-I deficiency [6]. Research continues into targeting specific IGFBPs to modulate tumor growth and metabolic health [7]. Sources: [1] UniProt Consortium, IGFBP family; [2] Firth, S. M., & Baxter, R. C. (2002), Endocrine Reviews; [3] Allard, J. B., & Duan, C. (2018), Frontiers in Endocrinology; [4] Bach, L. A. (2015), Journal of Molecular Endocrinology; [5] Hwa, V., et al. (2008), Endocrine Reviews; [6] FDA Label, IPLEX (Mecasermin rinfabate); [7] Baxter, R. C. (2014), Nature Reviews Cancer.

Other names

IGF-binding proteinsIBP-1 to IBP-6Insulin-like growth factor binding protein family

IGFBPs modulate the activity of IGF-I and IGF-II by sequestering them from their receptors or facilitating their delivery to the cell surface; they also exert IGF-independent effects through direct interaction with other signaling pathways or nuclear translocation.