Iron accumulation in the brain is associated with the pathogenesis of Parkinson's disease (PD). Misexpression of some iron transport and storage proteins is related to iron dyshomeostasis. Iron regulatory proteins (IRPs) including IRP1 and IRP2 are cytosolic proteins that play important roles in maintaining cellular iron homeostasis. F-box and leucine-rich repeat protein 5 (FBXL5) is involved in the regulation of iron metabolism by degrading IRP2 through the ubiquitin-proteasome system. Nitric oxide (NO) enhances the binding activity of IRP1, but its effect on IRP2 is ambiguous. Therefore, in the present study, we aim to determine whether sodium nitroprusside (SNP), a NO donor, regulates FBXL5 and IRP2 expression in cultured SH-SY5Y cells. MTT assay revealed that treatment of SNP attenuated the cell viability in a dose-dependent manner. Flow cytometry test showed that 100 and 300 μmol/L SNP administration significantly reduced the mitochondrial membrane potential by 45% and 60%, respectively. Moreover, Western blotting analysis demonstrated that 300 μmol/L SNP significantly increased FBXL5 expression by about 39%, whereas the expression of IRP2 was decreased by 46%, correspondingly. These findings provide evidence that SNP could induce mitochondrial dysfunction, enhance FBXL5 expression and decrease IRP2 expression in SH-SY5Y cells.
Cell Line ; Cell Survival ; F-Box Proteins ; metabolism ; Homeostasis ; Humans ; Iron Regulatory Protein 2 ; metabolism ; Nitric Oxide ; metabolism ; Nitroprusside ; pharmacology ; Proteasome Endopeptidase Complex ; Ubiquitin ; metabolism ; Ubiquitin-Protein Ligase Complexes ; metabolism

Ubiquitin is highly conserved 76 amino acid protein found in all eukaryotic organisms and ubiquitin-proteasome pathway (UPP) plays a very important role in regulated non-lysosomal ATP dependent protein degradation. This pathway participates in or regulates numerous cellular processes, such as selective protein degradation, cell cycle progression, apoptosis, signal transduction, transcriptional regulation, receptor control by endocytosis, immune response and the processing of antigens. Nevertheless, roles of UPP in virus infection are only beginning to be clarified. Ubiquitin homology has also been found in insect viruses. All viral ubiquitin genes encode an N-terminal ubiquitin sequence and 3-256 amino acids C-terminal peptides. Most of the residues known to be essential for ubiquitin function have been conserved in the viral variant. In Autographa californica nucleopolyhedrovirus (AcMNPV), viral ubiquitin is attached to the inner surface of budded viron membrane by a covalently linked phospholipid and is not essential for viral replication. Currently, insect viruses are the only viruses known to encode ubiquitin. However, ubiquitin also plays a role in the life cycle of other viruses. Host ubiquitin molecules have been found in some plant viruses and other animal viruses. Additionally, Africa swine fever virus (ASFV) encodes a ubiquitin-conjugating enzyme (E2) and a putative causal link between human immunodeficiency virus type 1 (HIV-1) and ubiquitin was established by showing that depletion of the intracellular pool of free ubiquitin inhibits the virus budding. Further analyses indicated that many retroviruses proteins which are required for efficient pinching off the virus bud contain a late domain. The core element of the late domain is a proline-rich motif (PPXY) which mediates the late domain to be ubiquitinated by cellular proteins. Recently, it has been shown that many retroviruses have developed mechanisms to escape the cellular immune response, to facilitate virus replication and to promote virus assembly and budding via host UPP.
African Swine Fever Virus ; metabolism ; pathogenicity ; Animals ; Humans ; Insect Viruses ; metabolism ; pathogenicity ; Proteasome Endopeptidase Complex ; metabolism ; Retroviridae ; metabolism ; pathogenicity ; Ubiquitin ; metabolism ; Ubiquitin-Protein Ligase Complexes ; metabolism ; Virus Diseases ; virology ; Viruses ; pathogenicity

OBJECTIVE: Previously, we found that oocyte specific homeobox (Obox) 4 plays significant role in completion of meiosis specifically at meiosis I-meiosis II (MI-MII) transition. The purpose of this study was to determine the mechanism of action of Obox4 in oocyte maturation by evaluating downstream signal networking. METHODS: The Obox4 dsRNA was prepared by in vitro transcription and microinjected into the cytoplasm of germinal vesicle oocytes followed by in vitro maturation in the presence or absence of 0.2 mM 3-isobutyl-1-metyl-xanthine. Total RNA was extracted from 200 oocytes of each group using a PicoPure RNA isolation kit then amplified two-rounds. The probe hybridization and data analysis were used by Affymetrix GeneChip(R) Mouse Genome 430 2.0 array and GenPlex 3.0 (ISTECH, Korea) software, respectively. RESULTS: Total 424 genes were up (n=80) and down (n=344) regulated after Obox4 RNA interference (RNAi). Genes mainly related to metabolic pathways and mitogen-activated protein kinase (MAPK) signaling pathway was changed. Among the protein kinase C (PKC) isoforms, PKC-alpha, beta, gamma were down-regulated and especially the MAPK signaling pathway PKC-gamma was dramatically decreased by Obox4 RNAi. In the cell cycle pathway, we evaluated the expression of genes involved in regulation of chromosome separation, and found that these genes were down-regulated. It may cause the aberrant chromosome segregation during MI-MII transition. CONCLUSION: From the results of this study, it is concluded that Obox4 is important upstream regulator of the PKC and anaphase-promoting complex action for maintaining intact germinal vesicle.
Animals ; Cell Cycle ; Chimera ; Chromosome Segregation ; Cytoplasm ; Gene Expression ; Genes, Homeobox ; Genome ; Meiosis ; Metabolic Networks and Pathways ; Mice ; Microarray Analysis ; Oocytes ; Protein Isoforms ; Protein Kinase C ; Protein Kinases ; RNA ; RNA Interference ; Statistics as Topic ; Ubiquitin-Protein Ligase Complexes

A recently identified protein, FAN1 (FANCD2-associated nuclease 1, previously known as KIAA1018), is a novel nuclease associated with monoubiquitinated FANCD2 that is required for cellular resistance against DNA interstrand crosslinking (ICL) agents. The mechanisms of FAN1 regulation have not yet been explored. Here, we provide evidence that FAN1 is degraded during mitotic exit, suggesting that FAN1 may be a mitotic substrate of the anaphase-promoting cyclosome complex (APC/C). Indeed, Cdh1, but not Cdc20, was capable of regulating the protein level of FAN1 through the KEN box and the D-box. Moreover, the up- and down-regulation of FAN1 affected the progression to mitotic exit. Collectively, these data suggest that FAN1 may be a new mitotic substrate of APC/CCdh1 that plays a key role during mitotic exit.
Anaphase-Promoting Complex-Cyclosome ; Bone Neoplasms ; metabolism ; pathology ; Cadherins ; genetics ; metabolism ; Cdc20 Proteins ; Cell Cycle Proteins ; genetics ; metabolism ; Cell Line, Tumor ; Exodeoxyribonucleases ; genetics ; metabolism ; HEK293 Cells ; Humans ; Mitosis ; Osteosarcoma ; metabolism ; pathology ; Ubiquitin-Protein Ligase Complexes ; genetics ; metabolism

CUE domain-containing 2 (CUEDC2) is a protein involved in the regulation of the cell cycle, inflammation, and tumorigenesis and is highly expressed in many types of tumors. CUEDC2 is phosphorylated by Cdk1 during mitosis and promotes the release of anaphase-promoting complex or cyclosome (APC/C) from checkpoint inhibition. CUEDC2 is also known to interact with IkB kinase α (IKKα) and IKKβ and has an inhibitory role in the activation of transcription factor nuclear factor-κB. Moreover, CUEDC2 plays an important role in downregulating the expression of hormone receptors estrogen receptor-α and progesterone receptor, thereby impairing the responsiveness of breast cancer to endocrine therapies. In this review, current knowledge on the multi-functions of CUEDC2 in normal processes and tumorigenesis are discussed and summarized.
Anaphase-Promoting Complex-Cyclosome ; Breast Neoplasms ; pathology ; Carrier Proteins ; metabolism ; Cell Cycle Proteins ; metabolism ; Cell Transformation, Neoplastic ; pathology ; Estrogen Receptor alpha ; metabolism ; Female ; Humans ; I-kappa B Kinase ; metabolism ; Inflammation ; pathology ; M Phase Cell Cycle Checkpoints ; Membrane Proteins ; metabolism ; Mitosis ; NF-kappa B p50 Subunit ; metabolism ; Receptor-Interacting Protein Serine-Threonine Kinases ; metabolism ; Signal Transduction ; Ubiquitin-Protein Ligase Complexes ; metabolism ; Ubiquitination

The ubiquitin-proteasome system plays an important role in protein degradation. The process of ubiquitination requires ubiquitin activating enzyme E1, ubiquitin-conjugating enzyme E2, and ubiquitin ligase E3 to complete the coordination. Our previous studies have shown that HUWE1 (HECT, UBA and WWE domain containing 1), as an E3 ubiquitin ligase, can degrade epidermal growth factor receptor (EGFR) to inhibit renal tubulointerstitial fibrosis. However, E2 ubiquitin-conjugating enzymes binding to HUWE1 are still unclear. The aim of the present study was to identify E2 ubiquitin-conjugating enzymes of HUWE1. Real-time PCR was used to identify E2 ubiquitin-conjugating enzyme that may interact with HUWE1. The expression of E2 ubiquitin-conjugating enzyme was detected in kidney of unilateral ureteral obstruction (UUO) mice and HK-2 cells treated with transforming growth factor-β (TGF-β). The results showed that the expressions of E2 ubiquitin-conjugating enzyme UBE2Q2 were significantly down-regulated at both RNA and protein levels in UUO kidneys. The expression of UBE2Q2 was also down-regulated in HK-2 cells stimulated with TGF-β, which was consistent with the change in the expression of HUWE1. These findings indicated that UBE2Q2 expression was synergistic with HUWE1 in the injured kidney. Co-immunoprecipitation (Co-IP) experiments showed that HUWE1 interacted with UBE2Q2 in HK-2 cells. The co-localization of UBE2Q2 and HUWE1 was confirmed by cell immunofluorescence staining. After knocking down UBE2Q2 by siRNA, ubiquitin binding to HUWE1 and EGFR was decreased. In sum, our results demonstrated that UBE2Q2, ubiquitin-conjugating enzyme, works with HUWE1 to mediate ubiquitination and degradation of target protein in kidney.
Animals ; Cell Line ; Fibrosis ; Humans ; Kidney Diseases ; Mice ; Ubiquitin-Conjugating Enzymes/metabolism* ; Ubiquitin-Protein Ligases/metabolism* ; Ubiquitination

OBJECTIVETo report the clinical characterization of a large Chinese kindred with von Hippel-Lindau (VHL) disease and to evaluate the role of VHL genetic testing in diagnosis of VHL disease and clinical screening for members in VHL disease family.

METHODSA large kindred with VHL disease was studied. DNA extracted from peripheral blood was amplified by PCR to three exons of VHL gene in 27 members. PCR products were directly sequenced. The data on involvement of multi-organs in the VHL disease kindred were obtained by medical history taking and radiography.

RESULTSThere were 47 members in the four generations of the Chinese VHL kindred; among them, 18 members were patients with diagnostically proven VHL disease. Their clinical manifestations included: central nervous system(CNS) hemangioblastoma (n=5), renal cell carcinomas and CNS hemangioblastoma (n=3), renal cell carcinomas and retinal angiomas (n=3), renal cell carcinomas and multiple pancreatic cysts (n=1), renal cell carcinomas and retinal angiomas and multiple pancreatic cysts (n=2), renal cell carcinomas and CNS hemangioblastomas and multiple pancreatic cysts (n=1), and multiple pancreatic cysts and multiple renal cysts (n=1), and multiple pancreatic cysts (n=2). The common lesions of 18 patients in the large kindred were: renal cell carcinomas (56%), CNS hemangioblastomas(50%),retinal angiomas(28%), and multiple pancreatic cysts(39%). Of the 27 members who volunteered for genetic analysis, all 11 affected family patients who are still alive, including 9 affected family patients and 2 asymptomatic patients, presented a codon 78 from Asn to Ser change at nucleotide 446(A to G) in exon 1. Four members were carriers with the same VHL gene mutation. Two asymptomatic cases were initially diagnosed by genetic testing and subsequently confirmed by radiological imaging and surgery. Members not having the gene mutation had no clinical evidence of VHL disease.

CONCLUSIONThe large Chinese kindred with VHL disease was classified as type . The main characteristics of the kindred are higher incidence of renal cell carcinomas and lower incidence of retinal angiomas. The genetic testing played an important role in early detecting asymptomatic patients and the carriers in clinical screening for members in the VHL families. Also, it is important to prevent the transmission of VHL disease to the offspring in the kindred.

Base Sequence ; China ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Family Health ; Female ; Genetic Testing ; Humans ; Male ; Mutation ; Pedigree ; Tumor Suppressor Proteins ; genetics ; Ubiquitin-Protein Ligases ; genetics ; Von Hippel-Lindau Tumor Suppressor Protein ; von Hippel-Lindau Disease ; classification ; diagnosis ; genetics

BACKGROUNDVon Hippel-Lindau (VHL) disease is a heraditary cancer syndrome caused by germline mutations of the VHL tumor on the suppressor gene. This study was to show the clinical characteristics of a large Chinese kindred with von Hippel-Lindau disease and to evaluate the role of the genetic test of VHL disease in the diagnosis of VHL disease and clinical screening of members of the VHL disease family.

METHODSDNA extracted from peripheral blood was amplified by PCR to three exons of the VHL gene in 27 members of a large kindred with VHL disease. PCR products were directly sequenced. The involvements of multi-organs in the kindred with VHL disease were confirmed by history taking and radiography.

RESULTSOf 47 members in the four generations of the kindred, 18 members were diagnosed as having VHL disease. Clinical manifestations of 18 patients included: central nervous system (CNS) hemangioblastoma (5), renal cell carcinoma and CNS hemangioblastoma (3), renal cell carcinoma and retinal angioma (3), renal cell carcinoma and multiple pancreatic cysts (1), renal cell carcinoma and retinal angioma and multiple pancreatic cysts (2), renal cell carcinoma and CNS hemangioblastomas and multiple pancreatic cysts (1), and multiple pancreatic cysts and multiple renal cysts (1), multiple pancreatic cysts (2). The common lesions of the 18 patients were renal cell carcinoma (55.6%), CNS hemangioblastoma (50.0%), retinal angioma (27.8%), and multiple pancreatic cysts (38.9%). Among the 27 members who volunteered for genetic analysis, 15 members including 9 affected family patients and 2 asymptomatic patients and 4 carriers, who are still alive, presented a codon 78 from Asn to Ser change at nucleotide 446 (A-->G) in exon 1. Four members were carriers with the same VHL gene mutation. Two asymptomatic patients were initially diagnosed by genetic testing and subsequently confirmed radiologically and surgically. Members without gene mutation had no clinical evidence of VHL disease.

CONCLUSIONSThe large Chinese kindred with VHL disease was classified as type I. The main characteristics in the kindred were higher incidence of renal cell carcinoma and lower incidence of retinal angioma. Genetic test plays an important role in early detecting asymptomatic patients and the carriers in clinical screening of members of the families with VHL disease. It is also important to prevent the transmission of VHL disease to their offsprings in the kindred.

Adolescent ; Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; Mutation ; Pedigree ; Tumor Suppressor Proteins ; genetics ; Ubiquitin-Protein Ligases ; genetics ; Von Hippel-Lindau Tumor Suppressor Protein ; von Hippel-Lindau Disease ; complications ; diagnosis ; genetics

Adult ; Aged ; Aged, 80 and over ; Carcinoma, Renal Cell ; genetics ; pathology ; Female ; Humans ; Kidney Neoplasms ; genetics ; pathology ; Loss of Heterozygosity ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Tumor Suppressor Proteins ; genetics ; Ubiquitin-Protein Ligases ; genetics ; Von Hippel-Lindau Tumor Suppressor Protein

The ubiquitin-proteasome system (UPS) is a proteasome system widely present in the human body, which is composed of ubiquitin (Ub), ubiquitin activating enzymes (E1), ubiquitin conjugating enzymes (E2), ubiquitin protein ligases (E3), 26S proteasome, and deubiquitinating enzymes (DUBs) and involved in cell cycle regulation, immune response, signal transduction, DNA repair as well as protein degradation. Sperm DNA is vulnerable to interference or damage in the progression of chromosome association and homologous recombination. Recent studies show that UPS participates in DNA repair in spermatogenesis by modulating DNA repair enzymes via ubiquitination, assisting in the identification of DNA damage sites, raising damage repair-related proteins, initiating the DNA repair pathway, maintaining chromosome stability, and ensuring the normal process of spermatogenesis.
Cell Cycle Proteins ; physiology ; DNA Damage ; DNA Repair ; physiology ; Humans ; Male ; Proteasome Endopeptidase Complex ; physiology ; Signal Transduction ; physiology ; Spermatogenesis ; physiology ; Spermatozoa ; Ubiquitin ; physiology ; Ubiquitin-Conjugating Enzymes ; physiology ; Ubiquitin-Protein Ligases ; physiology ; Ubiquitination