Hyaluronan and proteoglycan link protein 2 (HAPLN2)

Hyaluronan and proteoglycan link protein 2 (HAPLN2), also known as brain link protein 1 (BRAL1), is a brain-specific member of the hyaluronan and proteoglycan link protein family[1][3][2]. It is a structural component of the extracellular matrix (ECM) in the central nervous system, mediating the stable binding of chondroitin sulfate proteoglycans (such as versican V2 and brevican) to hyaluronic acid[1][3][2][4][5]. HAPLN2 is essential for establishing and maintaining ECM organization at nodes of Ranvier and plays a crucial role in supporting neuronal conduction and action potential propagation[1][3]. Its expression is most prominent in the hippocampus, thalamus, spinal cord, substantia nigra, and other brain regions[1][2]. HAPLN2 has emerging relevance in neurodegeneration, as it promotes α-synuclein aggregation in Parkinson’s disease and may be found in neurofibrillary tangles in Alzheimer’s disease[1]. It may also be involved in the structural deficits seen in schizophrenia[1]. No drugs are known to specifically target HAPLN2, and it is not currently considered a therapeutic target, but its restricted expression in the CNS and involvement in neurological disease pathogenesis make it a subject of continuing research interest[1][2][3][4][5].

Other names

Brain link protein 1BRAL1brain link protein-1hyaluronan and proteoglycan link protein 2HPLN2