Attenuation of inflammation and cartilage degradation by sulfasalazine-containing hyaluronic acid on osteoarthritis rat model.

The aim of this study was to investigate the effects of a sulfasalazine-containing hyaluronic acid (SASP/HA) systems on in vitro anti-inflammation and the alleviation of cartilage degradation in both lipopolysaccharide (LPS)-stimulated synoviocytes and a rat model of monosodium iodoacetate (MIA)-induced osteoarthritis (OA). The SASP/HA resulted in long-term release of SASP from the SASP/HA for up to 60 days in a sustained manner. In vitro studies performed using real-time polymerase chain reaction (PCR) assay revealed that the SASP/HA was able to effectively and dose-dependently inhibit the mRNA expression levels of pro-inflammatory cytokines such as matrix metalloproteinases-3 (MMP-3), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in LPS-stimulated synoviocytes.

C. elegans CAND-1 regulates cullin neddylation, cell proliferation and morphogenesis in specific tissues.

Cullin-RING ubiquitin ligases (CRLs) are critical regulators of multiple developmental and cellular processes in eukaryotes. CAND1 is a biochemical inhibitor of CRLs, yet has been shown to promote CRL activity in plant and mammalian cells. Here we analyze CAND1 function in the context of a developing metazoan organism.

A modified feeding RNAi method for simultaneous knock-down of more than one gene in Caenorhabditis elegans.

RNA interference (RNAi) is a commonly used technique for reverse genetic approaches in Caenorhabditis elegans. Feeding RNAi is the most convenient and inexpensive method for performing genome-wide RNAi screens. However, it has been reported that knock-down of two genes (double RNAi) by feeding RNAi using a mixture of bacteria that each contained one dsRNA species produced poor results.

Control of rapsyn stability by the CUL-3-containing E3 ligase complex.

Rapsyn is a postsynaptic protein required for clustering of nicotinic acetylcholine receptors (nAChRs) at the neuromuscular junction. Here we report the mechanism for posttranslational control of rapsyn protein stability. We confirmed that C18H9.

CAND1 enhances deneddylation of CUL1 by COP9 signalosome.

Cullin-RING ligases (CRLs) regulate diverse cellular functions such as cell cycle progression and cytokine signaling by ubiquitinating key regulatory proteins. The activity of CRLs is controlled by Nedd8 modification of the cullin subunits. Recent reports have suggested that CAND1, which specifically binds to unmodified CUL1 but not to neddylated one, is required for the in vivo function of SCFs, the CUL1-containing CRLs.

TIP120A associates with unneddylated cullin 1 and regulates its neddylation.

The cullin-containing E3 ubiquitin ligases play an important role in regulating the abundance of key proteins involved in cellular processes such as cell cycle and cytokine signaling. We recently identified TIP120A as a cullin-interacting protein and found that TIP120A functions as a negative regulator of a ubiquitin ligase by interfering with the binding of Skp1 and an F box protein to CUL1. Here we show that TIP120A binds to the unneddylated CUL1 but not the neddylated one.

TIP120A associates with cullins and modulates ubiquitin ligase activity.

The cullin-containing ubiquitin-protein isopeptide ligases (E3s) play an important role in regulating the abundance of key proteins involved in cellular processes such as cell cycle and cytokine signaling. They have multisubunit modular structures in which substrate recognition and the catalysis of ubiquitination are carried out by distinct polypeptides. In a search for proteins involved in regulation of cullin-containing E3 ubiquitin ligases we immunopurified CUL4B-containing complex from HeLa cells and identified TIP120A as an associated protein by mass spectrometry.