Molecular weight characterization of PRG4 proteins using multi-angle laser light scattering (MALLS)

Abstract

A variety of monomeric PRG4 proteins and a disulfide-bonded dimer/multimer are secreted by chondrocytes in bovine cartilage explants. The observed decrease in M(W)'s of monomeric PRG4 species upon RA may be due to the release of post-translationally cleaved fragments. Further study of these species will provide insight into the PRG4 molecular structure and function relationship.

Muscular loading of joints triggers cellular secretion of PRG4 into the joint fluid

“…Total protein concentration and PRG4 levels ( $379, $467 kDa bands; Steele et al, 2013;Ludwig et al, 2012) increased with increasing intensity of exercise, and became exhausted with exercise duration. These results are consistent with in vitro studies showing that dynamic shear forces stimulate PRG4 secretion (Nugent et al, 2006a;Neu et al, 2007;Grad et al, 2005).…”

In vitro friction testing of contact lenses and human ocular tissues: Effect of proteoglycan 4 (PRG4)

“…22.5 μL of dH 2 O from the 3rd wash bath suspended in NuPAGE LDS sample buffer. The heated and wash samples were loaded onto Novex 3-8% TrisAcetate gels for electrophoresis and Western blot, as described previously [41]. PRG4 was identified using PRG4 specific mAb 9G3 antibody [42] (kindly provided by Dr. Gregory Jay, Brown University).…”

Role of hydrophobicity on the adsorption of synovial fluid proteins and biolubrication of polycarbonate urethanes: Materials for permanent meniscus implants

“…The difference between PCU and mPCU is the presence of C18 chains at the surface of mPCU. Bovine proteoglycan 4 (PRG4) was isolated, purified and characterized as described previously [35,53]. Bovine serum albumin (98-99%), 1-Octadecanethiol 98% (HS(CH 2 ) 17 CH 3 ) and 11-Mercapto-1-Undecanol 97% (HSCH 2 (CH 2 ) 9 CH 2 OH) were from Sigma-Aldrich, Ltd. (St. Louis, MO).…”

“…PRG4 was dissolved in 10 mM PBS at 100 lg/mL [34,35], and bovine serum albumin was dissolved in 10 mM PBS at 5 mg/mL [37]; the mixture of PRG4 and albumin consisted of 100 lg/mL PRG4 and 5 mg/mL albumin in 10 mM PBS. PBS contained 150 mmol/L NaCl, similar to synovial fluid [38].…”

“…A high concentration of hyaluronan (HA) is responsible for the high viscosity of the fluid [32,33]. A glycoprotein proteoglycan 4 (PRG4, also known as lubricin) mainly secreted by superficial layer chondrocytes [34,35] and surface active phospholipids (SAPL) are known to be involved in the joint lubrication [17,36]. Albumin, a globular protein, is the most abundant protein present in synovial fluid [37].…”