Insulin-like growth factor-binding protein 2 (IGFBP-2) heparin-binding domain (IGFBP-2 HBD)

The Insulin-like growth factor-binding protein 2 (IGFBP-2) heparin-binding domain (HBD) is a critical functional region within the IGFBP-2 protein that mediates its interaction with glycosaminoglycans in the extracellular matrix and on the cell surface [1.3.1, 1.3.4]. IGFBP-2 contains two such domains: HBD1, located in the linker region, and HBD2, located in the C-terminal region [1.1.1]. These domains allow the protein to act as a local reservoir for insulin-like growth factors (IGFs) and facilitate IGF-independent signaling pathways [1.3.1, 1.3.5]. A key mechanism involves the HBD binding to receptor protein tyrosine phosphatase beta (RPTPβ), which inactivates the phosphatase and triggers the PTEN/Akt survival pathway [1.3.1, 1.3.4]. In oncology, the HBD is associated with increased tumor invasion, migration, and chemoresistance, particularly in glioblastoma and neuroblastoma [1.3.3]. Conversely, in metabolic and skeletal health, HBD-derived peptides have shown potential as anabolic agents to increase bone mass and inhibit adipogenesis [1.1.1, 1.2.1]. Therapeutic strategies targeting this domain include synthetic peptides and antibodies designed to either mimic its beneficial metabolic effects or block its pro-tumorigenic interactions [1.1.1, 1.4.2].

Other names

IGFBP-2 HBD1IGFBP-2 HBD2Heparin-binding motif of IGFBP-2IBP-2 HBD

The heparin-binding domain (HBD) of IGFBP-2 mediates interactions with the extracellular matrix and cell surface proteoglycans, as well as the receptor protein tyrosine phosphatase beta (RPTPβ). Binding to RPTPβ leads to its inactivation, which subsequently inhibits PTEN and activates the PI3K/Akt signaling pathway. Additionally, the HBD can function as a nuclear localization sequence, facilitating the translocation of IGFBP-2 to the nucleus where it modulates the transcription of genes such as VEGF [1.3.1, 1.3.4].