Hyaluronan and proteoglycan link protein 1 (HAPLN1)

Hyaluronan and proteoglycan link protein 1 (HAPLN1) is an extracellular matrix protein in the hyaladherin family that functions as a structural component in connective tissues such as cartilage, skin, and blood vessels[1][2]. HAPLN1 is characterized by its ability to non-covalently bind hyaluronic acid and proteoglycans—such as aggrecan—to form highly stable ternary complexes, resulting in a viscoelastic matrix that provides tissues with resistance to compression and mechanical stress[1][3]. Expression of HAPLN1 is highest in chondrogenic tissues and plays an essential role in cartilage development, integrity, and homeostasis. Beyond cartilage, HAPLN1 also contributes to vascular and skin extracellular matrix structure, modulates cellular senescence, and influences cell proliferation and migration through regulation of key signaling pathways including SIRT1, p53, and inflammatory cytokines[3][5]. Dysregulation of HAPLN1 has been implicated in various diseases, notably rheumatoid arthritis, cardiovascular disease, skin aging, and certain cancers[3][5]. While no approved drugs directly target HAPLN1, recombinant protein and modulation strategies (e.g., via metformin) are under investigation for regenerative or anti-inflammatory therapies[3][5].

Other names

CRTL1Cartilage-link proteinCartilage-linking protein 1Proteoglycan link proteinCartilage link proteinCRT1

Stabilization of extracellular matrix via formation of HA-proteoglycan complexes; Modulation of inflammatory signaling and senescence pathways, notably through SIRT1, p53, p21, p16, and cytokine inhibition