Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0265264 (HOS)
 1,119 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

BetaTrCP and HOS are closely related F-box proteins, which play key roles in ubiquitination and degradation of beta-catenin and IkappaB through associating with those phosphorylated substrates and recruiting SCF E3 ubiquitin ligase. Here we report that activation of Wnt/beta-catenin signal transduction pathway elevates betaTrCP levels but inhibits expression of HOS in 293T cells. Similar disparity is likely to exist in human colorectal tumors. In the NIH3T3 cells, which express HOS, but not betaTrCP, Wnt/beta-catenin signaling leads to inhibition of HOS promoter activity and NF-kappaB-driven transcription as well as to stabilization of beta-catenin. These results indicate that expression and activities of HOS are negatively regulated by Wnt/beta-catenin pathway.
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PMID:Inhibition of HOS expression and activities by Wnt pathway. 1185 Aug 14

NF-kappaB transcription factor is activated upon ubiquitination and subsequent proteolysis of its inhibitor IkappaB. The phosphorylation-dependent ubiquitination is mediated by SCF E3 ubiquitin ligase. In this study, we identified a novel murine F-box/WD40 repeat-containing protein, mHOS (a homologue of HOS/betaTrCP2). mHOS efficiently binds Skp1 protein (a 'core' component of SCF ubiquitin ligase), and phosphorylated IkappaB(alpha). We found that mHOS associates with SCF-ROC1 E3 ubiquitin ligase activity. We have also observed that mHOS is overexpressed in chemically-induced mouse skin tumors, and its overexpression (but not accelerated IkappaB phosphorylation) coincides with the accelerated degradation of IkappaB in vivo. The role of mHOS in the constitutive activation of NF-kappaB in skin carcinogenesis is discussed.
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PMID:Mouse homologue of HOS (mHOS) is overexpressed in skin tumors and implicated in constitutive activation of NF-kappaB. 1189 78

Host cell factors can either positively or negatively regulate the assembly and egress of HIV-1 particles from infected cells. Recent reports have identified a previously uncharacterized transmembrane protein, tetherin/CD317/BST-2, as a crucial host restriction factor that acts during a late budding step in HIV-1 replication by inhibiting viral particle release. Although tetherin has been shown to promote the retention of nascent viral particles on the host cell surface, the precise molecular mechanisms that occur during and after these tethering events remain largely unknown. We here report that a RING-type E3 ubiquitin ligase, BCA2 (Breast cancer-associated gene 2; also called Rabring7, ZNF364 or RNF115), is a novel tetherin-interacting host protein that facilitates the restriction of HIV-1 particle production in tetherin-positive cells. The expression of human BCA2 in "tetherin-positive" HeLa, but not in "tetherin-negative" HOS cells, resulted in a strong restriction of HIV-1 particle production. Upon the expression of tetherin in HOS cells, BCA2 was capable of inhibiting viral particle production as in HeLa cells. The targeted depletion of endogenous BCA2 by RNA interference (RNAi) in HeLa cells reduced the intracellular accumulation of viral particles, which were nevertheless retained on the plasma membrane. BCA2 was also found to facilitate the internalization of HIV-1 virions into CD63(+) intracellular vesicles leading to their lysosomal degradation. These results indicate that BCA2 accelerates the internalization and degradation of viral particles following their tethering to the cell surface and is a co-factor or enhancer for the tetherin-dependent restriction of HIV-1 release from infected cells.
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PMID:BCA2/Rabring7 promotes tetherin-dependent HIV-1 restriction. 2001 14

F-box proteins are essential components of the Skp-cullin-F-box complex (a type of E3 ubiquitin ligase), and participate in cell cycle and immune responses through the ubiquitin proteasome system. F-box protein 39 (FBXO39) belongs to the F-box family, which has been reported to be associated with cancer oncogenesis and progression. The present study aimed to investigate the role of FBXO39 in osteosarcoma (OS) cell proliferation and apoptosis in vitro. It was demonstrated that U-2OS cells exhibited high expression of FBXO39 compared with HOS and SaOS-2 osteosarcoma cells. Thus, knockdown of FBXO39 was performed using lentivirus-mediated short hairpin RNA (shRNA) transfection to validate the effect of FBXO39 in U-2OS cells. Western blotting and RT-qPCR analysis were used to confirm the efficiency of infection by analyzing the expression level of FBXO39. Using Celigo-based cell counting and MTT assays, it was demonstrated that FBXO39 knockdown significantly reduced the rate of cell proliferation compared with control. Caspase 3/7 activity assays and fluorescence-activated cell sorting confirmed the induction of apoptosis in U-2OS cells following FBXO39 knockdown. In conclusion, it was demonstrated that FBXO39 knockdown may significantly inhibit proliferation and promote apoptosis of U-2OS cells. Thus, FBXO39 may serve an important role in OS progression.
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PMID:Knockdown of FBXO39 inhibits proliferation and promotes apoptosis of human osteosarcoma U-2OS cells. 3000 75