KIAA1199, a deafness gene of unknown function, is a new hyaluronan binding protein involved in hyaluronan depolymerization

Abstract

Hyaluronan (HA) has an extraordinarily high turnover in physiological tissues, and HA degradation is accelerated in inflammatory and neoplastic diseases. CD44 (a cell surface receptor) and two hyaluronidases (HYAL1 and HYAL2) are thought to be responsible for HA binding and degradation; however, the role of these molecules in HA catabolism remains controversial. Here we show that KIAA1199, a deafness gene of unknown function, plays a central role in HA binding and depolymerization that is independent of CD44 and HYAL enzymes. The specific binding of KIAA1199 to HA was demonstrated in glycosaminoglycan-binding assays. We found that knockdown of KIAA1199 abolished HA degradation by human skin fibroblasts and that transfection of KIAA1199 cDNA into cells conferred the ability to catabolize HA in an endo-β-N-acetylglucosaminidase-dependent manner via the clathrin-coated pit pathway. Enhanced degradation of HA in synovial fibroblasts from patients with osteoarthritis or rheumatoid arthritis was correlated with increased levels of KIAA1199 expression and was abrogated by knockdown of KIAA1199. The level of KIAA1199 expression in uninflamed synovium was less than in osteoarthritic or rheumatoid synovium. These data suggest that KIAA1199 is a unique hyaladherin with a key role in HA catabolism in the dermis of the skin and arthritic synovium. HA is ubiquitously present as a major constituent of the extracellular matrix (ECM) in vertebrate tissues, providing structural and functional integrity to cells and organs. Although many organs maintain high concentrations of HA, skin contains approximately half the total body HA (1). HA is rapidly depolymerized within tissues, from extralarge native molecules of 1,000-10,000 kDa, to intermediate-size fragments of 10-100 kDa present in the extracellular milieu (2). Approximately one-third of total body HA is replaced daily, and the skin is a major determinant organ for HA turnover, with a metabolic half-life of 1-1.5 d (2). HA degradation is enhanced under certain pathological conditions and its lower molecular weight products are commonly detected in diseases, such as arthritis and cancers (3-5). The reduced average molecular weight of HA (as low as 200 kDa) in synovial fluids from patients with osteoarthritis (OA) or rheumatoid arthritis (RA) leads to decreased synovial viscosity and is associated with synovial inflammation (6). In addition, much lower molecular weight HA fragments (∼20 kDa) are known to stimulate neovascularization and facilitate tumor cell motility and invasion (5,7,8).There are six human hyaluronidase-related genes clustered on two chromosomal loci, 3p21.3 (HYAL1, HYAL2, and HYAL3) and 7q31.3 (HYAL4, HYALP1, and SPAM1) (9). However, because HYALP1 is a pseudogene (9), and HYAL4 and SPAM1 have restricted expression patterns, HYALP1, HYAL4, and SPAM1 are unlikely to have major roles in constitutive HA degradation in vivo. HYAL3 has a restricted expression pattern (9) and its ability to degrade HA is questionable (10). Therefore, HYAL1 and HYAL2 are most likely ...

Regulation of Hyaluronan (HA) Metabolism Mediated by HYBID (Hyaluronan-binding Protein Involved in HA Depolymerization, KIAA1199) and HA Synthases in Growth Factor-stimulated Fibroblasts

“…Inhibitors and Activator-The pharmacologic inhibitors including p38-MAPK (mitogen-activated protein kinase) 3 H]HA of Ͼ1000 kDa was prepared as described previously (9). Cellular HA depolymerization was assayed by culturing confluent cells in medium containing [ 3 H]HA (40,000 dpm/ml) and applying the media to a Sepharose CL-2B (GE Healthcare) column (1 ϫ 60 cm) equilibrated with 0.5 M NaCl in distilled water.…”

“…Antibodies-A rat monoclonal antibody against HYBID was previously developed using a peptide of CARYSPHQ-DADPLKPRE, which corresponds to the amino acid residues Ala 762 to Glu 777 of KIAA1199 (GenBank TM accession number NM_018689) (9). An antibody against GAPDH was purchased from Santa Cruz Biotechnology.…”

“…We recently reported that KIAA1199, a novel HA-binding protein, plays a key role in HA degradation in normal human skin fibroblasts independently of the two hyaluronidases HYAL1 and HYAL2 and the cell surface HA receptor CD44 (9 -11). This molecule is also involved in HA degradation in synovial fibroblasts and is overexpressed in OA and RA synovial fibroblasts, showing correlation with enhanced HA-degrading activity (9). In the present study, because of the involvement in HA depolymerization, we propose to designate KIAA1199 as "HYBID" (HYaluronan-Binding protein Involved in hyaluronan Depolymerization).…”

A mammalian homolog of the zebrafish transmembrane protein 2 (TMEM2) is the long-sought-after cell-surface hyaluronidase

“…Other than the HYAL family molecules, the cell migrationinducing and hyaluronan-binding protein (CEMIP), also known as KIAA1199, has HA-binding and -degrading activities (16). CEMIP is a putative secretory protein containing an N-terminal signal sequence, and therefore it is considered to be a strong candidate as a hyaluronidase that acts in the extracellular space.…”

Platelet hyaluronidase-2: an enzyme that translocates to the surface upon activation to function in extracellular matrix degradation

“…17,19 KIAA1199 has recently been identified as an HAbinding protein and a contributor to HA degradation. 20 HA digestion can also occur by nonenzymatic mechanisms, mainly through reactive oxygen species. 21,22 We previously reported that mouse and human platelets and their megakaryocytic precursors express both HYAL2 messenger RNA and protein with no evidence for HYAL1.…”