Recombinant Human HAPLN1 protein

Hyaluronan and proteoglycan link protein 1 (HAPLN1), also known as cartilage link protein 1 (CRTL1), is a key extracellular matrix (ECM) component that stabilizes interactions between hyaluronan (HA) and proteoglycans such as aggrecan. This glycoprotein plays a critical role in maintaining the structural integrity and hydration of tissues, particularly in cartilage, the vitreous humor of the eye, and other HA-rich environments. By binding to both HA and aggrecan, HAPLN1 facilitates the formation of high-molecular-weight complexes that confer mechanical resilience, shock absorption, and elasticity to tissues. Its presence is essential for normal joint function, as it prevents HA degradation and ensures ECM stability under physiological stress.

Structurally, HAPLN1 contains two conserved domains: an N-terminal HA-binding region and a C-terminal link module shared with other proteoglycan-associated proteins. These domains enable its dual role in crosslinking HA and stabilizing proteoglycan networks. Dysregulation of HAPLN1 has been implicated in degenerative conditions like osteoarthritis, where reduced expression correlates with cartilage erosion and ECM breakdown. Conversely, its overexpression is observed in certain cancers, suggesting a role in tumor microenvironment modulation.

Recombinant HAPLN1 is produced using mammalian expression systems (e.g., CHO or HEK293 cells) to ensure proper post-translational modifications, such as disulfide bonding, which are critical for its biological activity. It serves as a vital tool for studying ECM dynamics, tissue engineering, and disease mechanisms. In regenerative medicine, recombinant HAPLN1 is explored for enhancing scaffold-based cartilage repair or modulating HA-dependent cellular behaviors in 3D culture models. Its therapeutic potential is also being investigated for restoring ECM homeostasis in joint diseases or counteracting pathological ECM remodeling in cancer metastasis.