Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monoubiquitination of the FANCD2 protein is a key step in the Fanconi anemia (FA) tumor suppressor pathway, coinciding with this molecule's accumulation at sites of genome damage. Strong circumstantial evidence points to a requirement for the BRCA1 gene product in this step. Here, we show that the purified BRCA1/BARD1 complex, together with E1 and UbcH5a, is sufficient to reconstitute the monoubiquitination of FANCD2 in vitro. Although siRNA-mediated knockdown of BRCA1 in human cells results in defective targeting of FANCD2 to sites of DNA damage, it does not lead to a defect in FANCD2 ubiquitination. Furthermore, ablation of the RING finger domains of either BRCA1 or BARD1 in the chicken B cell line DT40 also leaves FANCD2 modification intact. Consequently, while BRCA1 affects the accumulation of FANCD2 at sites of DNA damage, BRCA1/BARD1 E3 ligase activity is not essential for the monoubiquitination of FANCD2.
Mol Cell 2003 Jul
PMID:BRCA1-independent ubiquitination of FANCD2. 1288 9

The oculocerebrorenal syndrome of Lowe (OCRL) is a rare X-linked disorder characterized by severe mental retardation, congenital cataracts and renal Fanconi syndrome. OCRL1 protein is a phosphatidylinositol 4,5-bisphosphate 5-phosphatase with a C-terminal RhoGAP domain. Considering the pleiotropic cellular functions of Rho GTPases (Rho, Rac and Cdc42) and their dysregulation in several forms of mental retardation, we have investigated the so far unexplored function of the RhoGAP domain of OCRL1. Activated Rac GTPase was found to stably associate with the OCRL1 RhoGAP domain in vitro and to co-immunoprecipitate with endogenous OCRL1. Contrasting with other GAPs, OCRL1 RhoGAP exhibited a significant interaction with GDP bound Rac in vitro. As compared to Rac, other Rho GTPases tested showed reduced (Cdc42) or no binding (RhoA, RhoG) to OCRL1 RhoGAP. Immunofluorescence studies in HEK and COS7 cells and Golgi perturbation assays with Brefeldin A demonstrated that a fraction of endogenous Rac co-localizes with OCRL1 and gamma-adaptin in the trans-Golgi network. The OCRL1 RhoGAP domain showed low Rac GAP activity in vitro, and when expressed in Swiss 3T3 cells induced specific inhibition of RacGTP dependent ruffles, consistent with OCRL1 being an active RacGAP. OCRL1 appears to be a bifunctional protein which, in addition to its PIP2 5-phosphatase activity, binds to Rac GTPase. This novel property may play a role in localizing OCRL1 to the trans-Golgi network. Moreover, loss of OCRL1 RhoGAP and the resulting alteration in Rho pathways may contribute to mental retardation in Lowe syndrome, as illustrated in other forms of X-linked mental retardation.
Hum Mol Genet 2003 Oct 01
PMID:Lowe syndrome protein OCRL1 interacts with Rac GTPase in the trans-Golgi network. 1291 45

Fanconi anaemia (FA) is an autosomal recessive genetic disorder characterized by progressive bone marrow failure, multiple congenital abnormalities, and an increased risk of cancer. FA cells are characterized by chromosomal instability and hypersensitivity to DNA interstrand crosslinking agents. At least eight complementation groups exist (FA-A to G), and the genes for all of these except FA-B have been cloned. Functional linkage between the FA pathway and genes involved in susceptibility to breast cancer has been demonstrated by the interaction of the FANCA and FANCD2 proteins with BRCA1, and the discovery that the FANCD1 gene is identical to BRCA2. Here we have used the yeast two-hybrid system to test for direct interaction between BRCA2 or its effector RAD51 and the FANCA, FANCC and FANCG proteins. We found that FANCG was capable of binding to two separate sites in the BRCA2 protein, located either side of the BRC repeats. Furthermore, FANCG could be co-immunoprecipitated with BRCA2 from human cells, and FANCG co-localized in nuclear foci with both BRCA2 and RAD51 following DNA damage with mitomycin C. These results demonstrate that BRCA2 is directly connected to a pathway that is deficient in interstrand crosslink repair, and that at least one other FA protein is closely associated with the homologous recombination DNA repair machinery.
Hum Mol Genet 2003 Oct 01
PMID:Direct interaction of the Fanconi anaemia protein FANCG with BRCA2/FANCD1. 1291 60

Fanconi anemia (FA) is an autosomal recessive disease characterized by progressive bone marrow failure due to defective stem cell function. FA patients' cells are hypersensitive to DNA cross-linking agents such as mitomycin C (MMC), exposure to which results in cytogenetic aberrations and cell death. To date Moloney murine leukemia virus vectors have been used in clinical gene therapy. Recently, third-generation lentiviral vectors based on the HIV-1 genome have been developed for efficient gene transfer to hematopoietic stem cells. We generated a self-inactivating lentiviral vector expressing the FA group A cDNA driven by the murine stem cell virus U3 LTR promoter and used the vector to transduce side-population (SP) cells isolated from bone marrow of Fanconi anemia group A (Fanca) knockout mice. One thousand transduced SP cells reconstituted the bone marrow of sublethally irradiated Fanca recipient mice. Phenotype correction was demonstrated by stable hematopoiesis following MMC challenge. Using real-time PCR, one proviral vector DNA copy per cell was detected in all lineage-committed cells in the peripheral blood of both primary and secondary recipients. Our results suggest that the lentiviral vector transduces stem cells capable of self-renewal and long-term hematopoiesis in vivo and is potentially useful for clinical gene therapy of FA hematopoietic cells.
Mol Ther 2003 Oct
PMID:Phenotype correction of Fanconi anemia group A hematopoietic stem cells using lentiviral vector. 1452 33

Tumorigenesis can be viewed as an imbalance between the mechanisms of cell-cycle control and mutation rates within the genes. Genomic instability is broadly classified into microsatellite instability (MIN) associated with mutator phenotype, and chromosome instability (CIN) recognized by gross chromosomal abnormalities. Three intracellular mechanisms are involved in DNA damage repair that leads to mutator phenotype. They include the nucleotide excision repair (NER), base excision repair (BER) and mismatch repair (MMR). The CIN pathway is typically associated with the accumulation of mutations in tumor suppressor genes and oncogenes. Defects in DNA MMR and CIN pathways are responsible for a variety of hereditary cancer predisposition syndromes including hereditary non-polyposis colorectal carcinoma (HNPCC), Bloom syndrome, ataxia-telangiectasia, and Fanconi anaemia. While there are many genetic contributors to CIN and MIN, there are also epigenetic factors that have emerged to be equally damaging to cell-cycle control. Hypermethylation of tumor suppressor and DNA MMR gene promoter regions, is an epigenetic mechanism of gene silencing that contributes to tumorigenesis. Telomere shortening has been shown to increase genetic instability and tumor formation in mice, underscoring the importance of telomere length and telomerase activity in maintaining genomic integrity. Mouse models have provided important insights for discovering critical pathways in the progression to cancer, as well as to elucidate cross talk among different pathways. This review examines various molecular mechanisms of genomic instability and their relevance to cancer.
Curr Mol Med 2003 Nov
PMID:Genomic instability and cancer. 1460 34

The detailed mechanisms of DNA interstrand cross-link (ICL) repair and the involvement of the Fanconi anemia (FA)/BRCA pathway in this process are not known. Present models suggest that recognition and repair of ICL in human cells occur primarily during the S phase. Here we provide evidence for a refined model in which ICLs are recognized and are rapidly incised by ERCC1/XPF independent of DNA replication. However, the incised ICLs are then processed further and DNA double-strand breaks (DSB) form exclusively in the S phase. FA cells are fully proficient in the sensing and incision of ICL as well as in the subsequent formation of DSB, suggesting a role of the FA/BRCA pathway downstream in ICL repair. In fact, activation of FANCD2 occurs slowly after ICL treatment and correlates with the appearance of DSB in the S phase. In contrast, activation is rapid after ionizing radiation, indicating that the FA/BRCA pathway is specifically activated upon DSB formation. Furthermore, the formation of FANCD2 foci is restricted to a subpopulation of cells, which can be labeled by bromodeoxyuridine incorporation. We therefore conclude that the FA/BRCA pathway, while being dispensable for the early events in ICL repair, is activated in S-phase cells after DSB have formed.
Mol Cell Biol 2004 Jan
PMID:Repair kinetics of genomic interstrand DNA cross-links: evidence for DNA double-strand break-dependent activation of the Fanconi anemia/BRCA pathway. 1467 48

We have reviewed the world's literature that addresses familial leukemia, lymphoma, and myeloma. We have catalogued the phenotypic abnormalities associated with an increased risk of developing a hematological malignancy. These syndromes, such as Fanconi anemia or familial platelet syndrome, have been well characterized and in many cases the gene responsible for the predisposition has been defined. We have focused, however, on reports of a familial incidence of hematological malignancy in which no prior predisposing syndrome was reported. In this circumstance, so-called pure familial leukemia, lymphoma, or myeloma, the intergenerational incidence of disease occurred in ostensibly healthy persons. These families have been grouped into sets in which (a) anticipation, (b) immune abnormalities, (c) linkage to HLA phenotypes, (d) linkage to chromosome abnormalities, or (e) gene abnormalities have been reported. They have also been grouped by type of leukemia. Purely descriptive reports, not accompanied by some information on pathogenesis, have not been included. They are catalogued in some of the references cited in this paper. Anticipation is a prominent feature of familial leukemia, lymphoma, and myeloma, supporting the concept of germline transmission of a susceptibility gene. Although linkage to an HLA phenotype occurs in some families, no consistent intrafamilial pattern has emerged. Deletion of chromosome 7 is associated with familial acute myelogenous leukemia, but no other recurring localization has been established. Although putative susceptibility genes have been identified in some families, the likelihood is that the mode of inheritance is different in different families and different genes are involved even within a specific Mendelian pattern. Although as yet not reported, the frequency of familial CLL and the intensity of its study indicates that the gene or genes involved in that familial disorder(s) should be identified conclusively soon if sufficient families for study can be assembled through international cooperation.
Blood Cells Mol Dis
PMID:Familial (inherited) leukemia, lymphoma, and myeloma: an overview. 1475 42

Isolated renal glucosuria results from mutations in SGLT2, which codes for an active transporter specific for d-glucose and expressed in the luminal membrane of the renal proximal tubule. In affected individuals, glucosuria leads to pursuit of hyperglycemia to exclude defects in glucose metabolism, and to investigation of renal proximal tubular function to exclude renal Fanconi syndrome. Here we present clinical and molecular data regarding a 19-year-old woman with isolated glucosuria. She was compound heterozygous for two SGLT2 mutations, i.e., a new missense mutation, T200K, and a known missense mutation, N654S.
Mol Genet Metab 2004 May
PMID:Renal glucosuria due to SGLT2 mutations. 1511 Mar 22

Fanconi anaemia (FA) is a chromosomal instability disorder characterized by cellular sensitivity to DNA interstrand crosslinking agents and a high risk of cancer. Six of the eight proteins encoded by the known FA genes form a nuclear complex which is required for the monoubiquitination of the FANCD2 protein. FANCD2 complexes and colocalizes with BRCA1, but its presumptive role in DNA repair has not yet been clearly defined. We used yeast two-hybrid analysis to test for interaction between FANCD2 and 10 proteins involved in homologous recombination repair. FANCD2 did not interact with RAD51, the five RAD51 paralogs, RAD52, RAD54 or DMC1. However, it bound to a highly conserved C-terminal site in BRCA2 that also binds FANCG/XRCC9. FANCD2 and BRCA2 can be coimmunoprecipitated from cell extracts of both human and Chinese hamster wild-type cells, thus confirming that the interaction occurs in vivo. Formation of nuclear foci of FANCD2 was normal in the BRCA2 mutant CAPAN-1 cells, which indicates that the recruitment of FANCD2 to sites of DNA-repair is independent of wild-type BRCA2 function. FANCD2 colocalized with RAD51 in foci following treatment with mitomycin C or hydroxyurea, and colocalized very tightly with PCNA after treatment with hydroxyurea. These findings suggest that FANCD2 may have a role in the cellular response to stalled replication forks or in the repair of replication-associated double-strand breaks, irrespective of the type of primary DNA lesion.
Hum Mol Genet 2004 Jun 15
PMID:Direct interaction of FANCD2 with BRCA2 in DNA damage response pathways. 1511 58

Cystinosis is an inherited disorder characterized by defective lysosomal efflux of cystine. Three clinical forms (infantile, juvenile and ocular cystinosis) have been described according to the age of onset and severity of the symptoms. The causative gene, CTNS, encodes a seven transmembrane domain protein, cystinosin, which we recently identified as a H+-driven cystine transporter using an in vitro transport assay. In this study, we explored the relationship between transport activity and intracellular localization of cystinosin mutants and their associated clinical phenotype. Thirty-one pathogenic mutations (24 missense mutations, seven in-frame deletions or insertions) were analysed. Most of the mutations did not alter the lysosomal localization of cystinosin, although three partially mislocalized the protein independently of its C-terminal sorting motif, thus confirming the presence of an additional sorting mechanism. Sixteen of 19 mutations associated with infantile cystinosis abolished transport, whereas three of five mutations associated with juvenile or ocular forms strongly reduced transport, in agreement with the milder clinical phenotype. Five atypical, unclassified or misclassified mutations could be clarified using the transport data and additional genetic information. Overall, our data demonstrate that, excluding premature termination of cystinosin, impaired transport is the most frequent cause of pathogenicity, with infantile cystinosis generally resulting from a total loss of activity. Thus the transport assay could be used as a prognostic tool when novel mutations are identified.
Hum Mol Genet 2004 Jul 01
PMID:Molecular pathogenesis of cystinosis: effect of CTNS mutations on the transport activity and subcellular localization of cystinosin. 1512 4


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