| 1. |
- Dossus, Laure, et al.
(author)
-
PTGS2 and IL6 genetic variation and risk of breast and prostate cancer : results from the Breast and Prostate Cancer Cohort Consortium (BPC3)
- 2010
-
In: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 31:3, s. 455-461
-
Journal article (peer-reviewed)abstract
- Genes involved in the inflammation pathway have been associated with cancer risk. Genetic variants in the interleukin-6 (IL6) and prostaglandin-endoperoxide synthase-2 (PTGS2, encoding for the COX-2 enzyme) genes, in particular, have been related to several cancer types, including breast and prostate cancers. We conducted a study within the Breast and Prostate Cancer Cohort Consortium to examine the association between IL6 and PTGS2 polymorphisms and breast and prostate cancer risk. Twenty-seven polymorphisms, selected by pairwise tagging, were genotyped on 6292 breast cancer cases and 8135 matched controls and 8008 prostate cancer cases and 8604 matched controls. The large sample sizes and comprehensive single nucleotide polymorphism tagging in this study gave us excellent power to detect modest effects for common variants. After adjustment for multiple testing, none of the associations examined remained statistically significant at P = 0.01. In analyses not adjusted for multiple testing, one IL6 polymorphism (rs6949149) was marginally associated with breast cancer risk (TT versus GG, odds ratios (OR): 1.32; 99% confidence intervals (CI): 1.00-1.74, P(trend) = 0.003) and two were marginally associated with prostate cancer risk (rs6969502-AA versus rs6969502-GG, OR: 0.87, 99% CI: 0.75-1.02; P(trend) = 0.002 and rs7805828-AA versus rs7805828-GG, OR: 1.11, 99% CI: 0.99-1.26; P(trend) = 0.007). An increase in breast cancer risk was observed for the PTGS2 polymorphism rs7550380 (TT versus GG, OR: 1.38, 99% CI: 1.04-1.83). No association was observed between PTGS2 polymorphisms and prostate cancer risk. In conclusion, common genetic variation in these two genes might play at best a limited role in breast and prostate cancers.
|
|
| 2. |
- Frandsen, Rasmus J N, et al.
(author)
-
Two novel classes of enzymes are required for the biosynthesis of aurofusarin in Fusarium graminearum.
- 2011
-
In: Journal of Biological Chemistry. - 1083-351X.
-
Journal article (peer-reviewed)abstract
- Previous studies have reported the functional characterization of nine out of eleven genes found in the gene cluster responsible for biosynthesis of the polyketide pigment aurofusarin in Fusarium graminearum. Here we reanalyse the function of a putative aurofusarin pump (AurT) and the two remaining orphan genes, aurZ and aurS. Targeted gene replacement of aurZ resulted in the discovery that the compound YWA1, rather than nor-rubrofusarin, is the primary product of F. graminearum polyketide synthase 12 (FgPKS12). AurZ is the first representative of a novel class of dehydratases that act on hydroxylated γ-pyrones. Replacement of the aurS gene resulted in accumulation of rubrofusarin, an intermediate that also accumulates when the GIP1, aurF or aurO genes in the aurofusarin cluster are deleted. Based on the shared phenotype and predicted subcellular localization we propose that AurS is a member of an extracellular enzyme complex (GIP1-AurF-AurO-AurS) responsible for converting rubrofusarin into aurofusarin. This implies that rubrofusarin, rather than aurofusarin, is pumped across the plasma membrane. Replacement of the putative aurofusarin pump aurT increased rubrofusarin to aurofusarin ratio, supporting that rubrofusarin is normally pumped across the plasma membrane. These results provide functional information on two novel classes of proteins and their contribution to polyketide pigment biosynthesis.
|
|
| 3. |
- Gu, Gucci Jijuan, 1984-, et al.
(author)
-
Elevated MARK2-Dependent Phosphorylation of Tau in Alzheimer's Disease
- 2013
-
In: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 33:3, s. 699-713
-
Journal article (peer-reviewed)abstract
- The appearance of neurofibrillary tangles (NFT), one of the major hallmarks of Alzheimer's disease (AD), is most likely caused by inappropriate phosphorylation and/or dephosphorylation of tau, eventually leading to the accumulation of NFTs. Enhanced phosphorylation of tau on Ser(262) is detected early in the course of the disease and may have a role in the formation of tangles. Several kinases such as microtubule-affinity regulating kinase (MARK), protein kinase A, calcium calmodulin kinase II, and checkpoint kinase 2 are known to phosphorylate tau on Ser(262) in vitro. In this study, we took advantage of the in situ proximity ligation assay to investigate the role of MARK2, one of the four MARK isoforms, in AD. We demonstrate that MARK2 interacts with tau and phosphorylates tau at Ser(262) in stably transfected NIH/3T3 cells expressing human recombinant tau. Staurosporine, a protein kinase inhibitor, significantly reduced the interaction between MARK2 and tau, and also phosphorylation of tau at Ser(262). Furthermore, we observed elevated interactions between MARK2 and tau in post-mortem human AD brains, compared to samples from non-demented elderly controls. Our results from transfected cells demonstrate a specific interaction between MARK2 and tau, as well as MARK2-dependent phosphorylation of tau at Ser(262). Furthermore, the elevated interactions between MARK2 and tau in AD brain sections suggests that MARK2 may play an important role in early phosphorylation of tau in AD, possibly qualifying as a therapeutic target for intervention to prevent disease progression.
|
|
| 4. |
- Gu, Gucci Jijuan, et al.
(author)
-
Role of Individual MARK Isoforms in Phosphorylation of Tau at Ser262 in Alzheimer's Disease
- 2013
-
In: Neuromolecular medicine. - : Springer. - 1535-1084 .- 1559-1174. ; 15:3, s. 458-469
-
Journal article (peer-reviewed)abstract
- The microtubule-affinity regulating kinase (MARK) family consists of four highly conserved members that have been implicated in phosphorylation of tau protein, causing formation of neurofibrillary tangles in Alzheimer’s disease (AD). Understanding of roles by individual MARK isoform in phosphorylating tau has been limited due to lack of antibodies selective for each MARK isoform. In this study, we first applied the proximity ligation assay on cells to select antibodies specific for each MARK isoform. In cells, a CagA peptide specifically and significantly inhibited tau phosphorylation at Ser262 mediated by MARK4 but not other MARK isoforms. We then used these antibodies to study expression levels of MARK isoforms and interactions between tau and individual MARK isoforms in postmortem human brains. We found a strong and significant elevation of MARK4 expression and MARK4–tau interactions in AD brains, correlating with the Braak stages of the disease. These results suggest the MARK4–tau interactions are of functional importance in the progression of AD and the results also identify MARK4 as a promising target for AD therapy.
|
|
