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Yasuda K, Watkins AA, Kochar GS, Wilson GE, Laskow B, Richez C, Bonegio RG, Rifkin IR. Interferon regulatory factor-5 deficiency ameliorates disease severity in the MRL/lpr mouse model of lupus in the absence of a mutation in DOCK2. PLoS One 2014; 9:e103478. [PMID: 25076492 PMCID: PMC4116215 DOI: 10.1371/journal.pone.0103478] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 07/01/2014] [Indexed: 11/18/2022] Open
Abstract
Interferon regulatory factor 5 (IRF5) polymorphisms are strongly associated with an increased risk of developing the autoimmune disease systemic lupus erythematosus. In mouse lupus models, IRF5-deficiency was shown to reduce disease severity consistent with an important role for IRF5 in disease pathogenesis. However these mouse studies were confounded by the recent demonstration that the IRF5 knockout mouse line contained a loss-of-function mutation in the dedicator of cytokinesis 2 (DOCK2) gene. As DOCK2 regulates lymphocyte trafficking and Toll-like receptor signaling, this raised the possibility that some of the protective effects attributed to IRF5 deficiency in the mouse lupus models may instead have been due to DOCK2 deficiency. We have therefore here evaluated the effect of IRF5-deficiency in the MRL/lpr mouse lupus model in the absence of the DOCK2 mutation. We find that IRF5-deficient (IRF5−/−) MRL/lpr mice develop much less severe disease than their IRF5-sufficient (IRF5+/+) littermates. Despite markedly lower serum levels of anti-nuclear autoantibodies and reduced total splenocyte and CD4+ T cell numbers, IRF5−/− MRL/lpr mice have similar numbers of all splenic B cell subsets compared to IRF5+/+ MRL/lpr mice, suggesting that IRF5 is not involved in B cell development up to the mature B cell stage. However, IRF5−/− MRL/lpr mice have greatly reduced numbers of spleen plasmablasts and bone marrow plasma cells. Serum levels of B lymphocyte stimulator (BLyS) were markedly elevated in the MRL/lpr mice but no effect of IRF5 on serum BLyS levels was seen. Overall our data demonstrate that IRF5 contributes to disease pathogenesis in the MRL/lpr lupus model and that this is due, at least in part, to the role of IRF5 in plasma cell formation. Our data also suggest that combined therapy targeting both IRF5 and BLyS might be a particularly effective therapeutic approach in lupus.
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Gangadharan A, Sreerekha MV, Whitehill J, Ham JH, Mackey D. The Pseudomonas syringae pv. tomato type III effector HopM1 suppresses Arabidopsis defenses independent of suppressing salicylic acid signaling and of targeting AtMIN7. PLoS One 2013; 8:e82032. [PMID: 24324742 PMCID: PMC3855835 DOI: 10.1371/journal.pone.0082032] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/21/2013] [Indexed: 12/31/2022] Open
Abstract
Pseudomonas syringae pv tomato strain DC3000 (Pto) delivers several effector proteins promoting virulence, including HopM1, into plant cells via type III secretion. HopM1 contributes to full virulence of Pto by inducing degradation of Arabidopsis proteins, including AtMIN7, an ADP ribosylation factor-guanine nucleotide exchange factor. Pseudomonas syringae pv phaseolicola strain NPS3121 (Pph) lacks a functional HopM1 and elicits robust defenses in Arabidopsis thaliana, including accumulation of pathogenesis related 1 (PR-1) protein and deposition of callose-containing cell wall fortifications. We have examined the effects of heterologously expressed HopM1Pto on Pph-induced defenses. HopM1 suppresses Pph-induced PR-1 expression, a widely used marker for salicylic acid (SA) signaling and systemic acquired resistance. Surprisingly, HopM1 reduces PR-1 expression without affecting SA accumulation and also suppresses the low levels of PR-1 expression apparent in SA-signaling deficient plants. Further, HopM1 enhances the growth of Pto in SA-signaling deficient plants. AtMIN7 contributes to Pph-induced PR-1 expression. However, HopM1 fails to degrade AtMIN7 during Pph infection and suppresses Pph-induced PR-1 expression and callose deposition in wild-type and atmin7 plants. We also show that the HopM1-mediated suppression of PR-1 expression is not observed in plants lacking the TGA transcription factor, TGA3. Our data indicate that HopM1 promotes bacterial virulence independent of suppressing SA-signaling and links TGA3, AtMIN7, and other HopM1 targets to pathways distinct from the canonical SA-signaling pathway contributing to PR-1 expression and callose deposition. Thus, efforts to understand this key effector must consider multiple targets and unexpected outputs of its action.
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Worthmann K, Leitges M, Teng B, Sestu M, Tossidou I, Samson T, Haller H, Huber TB, Schiffer M. Def-6, a novel regulator of small GTPases in podocytes, acts downstream of atypical protein kinase C (aPKC) λ/ι. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:1945-1959. [PMID: 24096077 PMCID: PMC5707189 DOI: 10.1016/j.ajpath.2013.08.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 08/21/2013] [Accepted: 08/26/2013] [Indexed: 11/23/2022]
Abstract
The atypical protein kinase C (aPKC) isotypes PKCλ/ι and PKCζ are both expressed in podocytes; however, little is known about differences in their function. Previous studies in mice have demonstrated that podocyte-specific loss of PKCλ/ι leads to a severe glomerular phenotype, whereas mice deficient in PKCζ develop no renal phenotype. We analyzed various effects caused by PKCλ/ι and PKCζ deficiency in cultured murine podocytes. In contrast to PKCζ-deficient podocytes, PKCλ/ι-deficient podocytes exhibited a severe actin cytoskeletal phenotype, reduced cell size, decreased number of focal adhesions, and increased activation of small GTPases. Comparative microarray analysis revealed that the guanine nucleotide exchange factor Def-6 was specifically up-regulated in PKCλ/ι-deficient podocytes. In vivo Def-6 expression is significantly increased in podocytes of PKCλ/ι-deficient mice. Cultured PKCλ/ι-deficient podocytes exhibited an enhanced membrane association of Def-6, indicating enhanced activation. Overexpression of aPKCλ/ι in PKCλ/ι-deficient podocytes could reduce the membrane-associated expression of Def-6 and rescue the actin phenotype. In the present study, PKCλ/ι was identified as an important factor for actin cytoskeletal regulation in podocytes and Def-6 as a specific downstream target of PKCλ/ι that regulates the activity of small GTPases and subsequently the actin cytoskeleton of podocytes.
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Scotland RL, Allen L, Hennings LJ, Post GR, Post SR. The ral exchange factor rgl2 promotes cardiomyocyte survival and inhibits cardiac fibrosis. PLoS One 2013; 8:e73599. [PMID: 24069211 PMCID: PMC3775766 DOI: 10.1371/journal.pone.0073599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 07/25/2013] [Indexed: 12/24/2022] Open
Abstract
Cardiomyocytes compensate to acute cardiac stress by increasing in size and contractile function. However, prolonged stress leads to a decompensated response characterized by cardiomyocyte death, tissue fibrosis and loss of cardiac function. Identifying approaches to inhibit this transition to a decompensated response may reveal important targets for treating heart failure. The Ral guanine nucleotide disassociation (RalGDS) proteins are Ras-interacting proteins that are upregulated by hypertrophic stimuli. The Ral guanine nucleotide dissociation stimulator-like 2 (Rgl2) is a member of the RalGDS family that modulates expression of hypertrophic genes in cardiomyocytes. However, the pathophysiologic consequence of increased Rgl2 expression in cardiomyoctyes remains unclear. To evaluate the effect of increasing Rgl2 activity in the heart, transgenic mice with cardiac-targeted over-expression of Rgl2 were generated. Although Ral activation was increased, there were no apparent morphologic or histological differences between the hearts of Rgl2 transgenic and nontransgenic mice indicating that increased Rgl2 expression had no effect on basal cardiac phenotype. To determine if Rgl2 modulates the cardiac response to stress, mice were infused with the ß-adrenergic receptor agonist, isoproterenol. Isoproterenol infusion increased heart mass in both Rgl2 transgenic and nontransgenic mice. However, unlike nontransgenic mice, Rgl2 transgenic mice showed no morphologic evidence of cardiomyocyte damage or increased cardiac fibrosis following isoproterenol infusion. Increased Rgl2 expression in cultured cardiomyocytes stimulated Ral activation and inhibited staurosporine-induced apoptosis via increased activation of PI3-kinase. Activation of the PI3-kinase signaling pathway was confirmed in hearts isolated from Rgl2 transgenic mice. Increased expression and function of Rgl2 in cardiomyocytes promotes activation of the PI3-kinase signaling cascade and protects from carciomyocyte death and pathologic cardiac fibrosis. Taken further, these results suggest that Rgl2 upregulation in hypertrophic hearts may be a protetive mechanism, and that Rgl2 may be a novel therapeutic target in treating heart disease.
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Youn BU, Kim K, Kim JH, Lee J, Moon JB, Kim I, Park YW, Kim N. SLAT negatively regulates RANKL-induced osteoclast differentiation. Mol Cells 2013; 36:252-7. [PMID: 23996528 PMCID: PMC3887978 DOI: 10.1007/s10059-013-0159-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 07/02/2013] [Accepted: 07/02/2013] [Indexed: 12/25/2022] Open
Abstract
RANKL induces the formation of osteoclasts, which are responsible for bone resorption. Herein, we investigated the role of SWAP-70-like adapter of T cells (SLAT) in RANKL-induced osteoclastogenesis. Expression levels of SLAT were reduced during RANKL-induced osteoclastogenesis. Overexpression of SLAT in BMMs inhibited TRAP-positive multinuclear osteoclast formation and attenuated the expression of NFATc1, which is an important modulator in osteoclastogenesis. Furthermore, silencing of SLAT by RNA interference enhanced osteoclast formation as well as NFATc1 expression. In addition, SLAT was involved in RANKL-induced JNK activation in osteoclasts. Taken together, our data suggest that SLAT acts as a negative modulator of RANKL-induced osteoclastogenesis.
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Wang Z, Li T, Zhang W, You L, Zhao Y, Xia M, Zhao H, Chen ZJ. Variants in DENND1A and LHCGR are associated with endometrioid adenocarcinoma. Gynecol Oncol 2012; 127:403-5. [PMID: 22902918 DOI: 10.1016/j.ygyno.2012.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 08/06/2012] [Accepted: 08/07/2012] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The aim of this study was to explore the polycystic ovary syndrome (PCOS) related single nucleotide polymorphisms (SNPs) rs13405728 (in gene LHCGR), rs13429458 (in gene THADA) and rs2479106 (in gene DENND1A) in women with endometrial carcinoma. METHODS We conducted a case-control study comprising 96 Han Chinese women with endometrial carcinoma, and 192 healthy controls. SNPs rs13405728, rs13429458 and rs2479106 were genotyped by polymerase chain reaction (PCR) and direct sequencing. The effects of body mass index (BMI) and age were evaluated using an unconditional logistic regression model adjusted for potential confounders. RESULTS The allele frequencies of SNPs rs2479106 and rs13405728 were significantly different (P<0.05) between endometrial carcinoma group and control group, and the difference was especially significant in the subgroup of endometrioid adenocarcinoma. Genotyping analysis showed that allele G in rs2479106 and allele A in rs13405728 could confer risk to endometrioid adenocarcinoma. CONCLUSIONS Our results suggest that SNPs rs2479106 in gene DENND1A and rs13405728 in gene LHCGR are associated with endometrioid adenocarcinoma.
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Sun Q, Han C, Liu L, Wang Y, Deng H, Bai L, Jiang T. Crystal structure and functional implication of the RUN domain of human NESCA. Protein Cell 2012; 3:609-17. [PMID: 22821014 PMCID: PMC4875354 DOI: 10.1007/s13238-012-2052-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 07/09/2012] [Indexed: 10/28/2022] Open
Abstract
NESCA, a newly discovered signaling adapter protein in the NGF-pathway, contains a RUN domain at its N-terminus. Here we report the crystal structure of the NESCA RUN domain determined at 2.0-Å resolution. The overall fold of the NESCA RUN domain comprises nine helices, resembling the RUN domain of RPIPx and the RUN1 domain of Rab6IP1. However, compared to the other RUN domains, the RUN domain of NESCA has significantly different surface electrostatic distributions at the putative GTPase-interacting interface. We demonstrate that the RUN domain of NESCA can bind H-Ras, a downstream signaling molecule of TrkA, with high affinity. Moreover, NESCA RUN can directly interact with TrkA. These results provide new insights into how NESCA participates in the NGF-TrkA signaling pathway.
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MESH Headings
- Adaptor Proteins, Signal Transducing/chemistry
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Amino Acid Sequence
- Binding Sites
- Crystallography, X-Ray
- Gene Expression
- Guanine Nucleotide Exchange Factors
- Humans
- Models, Molecular
- Molecular Sequence Data
- Nerve Growth Factor/chemistry
- Nerve Growth Factor/genetics
- Nerve Growth Factor/metabolism
- Oncogene Protein p21(ras)/chemistry
- Oncogene Protein p21(ras)/genetics
- Oncogene Protein p21(ras)/metabolism
- Protein Binding
- Protein Structure, Tertiary
- Receptor, trkA/chemistry
- Receptor, trkA/genetics
- Receptor, trkA/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sequence Homology, Amino Acid
- Signal Transduction
- rab GTP-Binding Proteins/chemistry
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Welt CK, Styrkarsdottir U, Ehrmann DA, Thorleifsson G, Arason G, Gudmundsson JA, Ober C, Rosenfield RL, Saxena R, Thorsteinsdottir U, Crowley WF, Stefansson K. Variants in DENND1A are associated with polycystic ovary syndrome in women of European ancestry. J Clin Endocrinol Metab 2012; 97:E1342-7. [PMID: 22547425 PMCID: PMC3387396 DOI: 10.1210/jc.2011-3478] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
CONTEXT A genome-wide association study has identified three loci (five independent signals) that confer risk for polycystic ovary syndrome (PCOS) in Han Chinese women. Replication is necessary to determine whether the same variants confer risk for PCOS in women of European ancestry. OBJECTIVE The objective of the study was to test whether these PCOS risk variants in Han Chinese women confer risk for PCOS in women of European ancestry. DESIGN This was a case-control study. SETTING The study was conducted at deCODE Genetics in Iceland and two academic medical centers in the United States. PATIENTS Cases were 376 Icelandic women and 565 and 203 women from Boston, MA, and Chicago, IL, respectively, all diagnosed with PCOS by the National Institutes of Health criteria. Controls were 16,947, 483, and 189 women not known to have PCOS from Iceland, Boston, and Chicago, respectively. INTERVENTION There were no interventions. MAIN OUTCOMES Main outcomes were allele frequencies for seven variants in PCOS cases and controls. RESULTS Two strongly correlated Han Chinese PCOS risk variants on chromosome 9q33.3, rs10986105[C], and rs10818854[A], were replicated in samples of European ancestry with odds ratio of 1.68 (P = 0.00033) and odds ratio of 1.53 (P = 0.0019), respectively. Other risk variants at 2p16.3 (rs13405728), 2p21 (rs12468394, rs12478601, and rs13429458), and 9q33.3 (rs2479106), or variants correlated with them, did not associate with PCOS. The same allele of rs10986105 that increased the risk of PCOS also increased the risk of hyperandrogenism in women without PCOS from Iceland and demonstrated a stronger risk for PCOS defined by the National Institutes of Health criteria than the Rotterdam criteria. CONCLUSIONS We replicated one of the five Chinese PCOS association signals, represented by rs10986105 and rs10818854 on 9q33, in individuals of European ancestry. Examination of the subjects meeting at least one of the Rotterdam criteria for PCOS suggests that the variant may be involved in the hyperandrogenism and possibly the irregular menses of PCOS.
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Fernandes H, Franklin E, Jollivet F, Bliedtner K, Khan AR. Mapping the interactions between a RUN domain from DENND5/Rab6IP1 and sorting nexin 1. PLoS One 2012; 7:e35637. [PMID: 22558185 PMCID: PMC3338420 DOI: 10.1371/journal.pone.0035637] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 03/19/2012] [Indexed: 12/03/2022] Open
Abstract
Eukaryotic cells have developed a diverse repertoire of Rab GTPases to regulate vesicle trafficking pathways. Together with their effector proteins, Rabs mediate various aspects of vesicle formation, tethering, docking and fusion, but details of the biological roles elicited by effectors are largely unknown. Human Rab6 is involved in the trafficking of vesicles at the level of Golgi via interactions with numerous effector proteins. We have previously determined the crystal structure of Rab6 in complex with DENND5, alternatively called Rab6IP1, which comprises two RUN domains (RUN1 and RUN2) separated by a PLAT domain. The structure of Rab6/RUN1-PLAT (Rab6/R1P) revealed the molecular basis for Golgi recruitment of DENND5 via the RUN1 domain, but the functional role of the RUN2 domain has not been well characterized. Here we show that a soluble DENND5 construct encompassing the RUN2 domain binds to the N-terminal region of sorting nexin 1 by surface plasmon resonance analyses.
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Jones ML, Murden SL, Bem D, Mundell SJ, Gissen P, Daly ME, Watson SP, Mumford AD. Rapid genetic diagnosis of heritable platelet function disorders with next-generation sequencing: proof-of-principle with Hermansky-Pudlak syndrome. J Thromb Haemost 2012; 10:306-9. [PMID: 22118648 DOI: 10.1111/j.1538-7836.2011.04569.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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87
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Hu C, Zhang R, Wang C, Wang J, Ma X, Hou X, Lu J, Yu W, Jiang F, Bao Y, Xiang K, Jia W. Variants from GIPR, TCF7L2, DGKB, MADD, CRY2, GLIS3, PROX1, SLC30A8 and IGF1 are associated with glucose metabolism in the Chinese. PLoS One 2010; 5:e15542. [PMID: 21103350 PMCID: PMC2984505 DOI: 10.1371/journal.pone.0015542] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 10/05/2010] [Indexed: 12/13/2022] Open
Abstract
Background Recent meta-analysis of genome-wide association studies in European descent samples identified novel loci influencing glucose and insulin related traits. In the current study, we aimed to evaluate the association between these loci and traits related to glucose metabolism in the Chinese. Methods/Principal Findings We genotyped seventeen single nucleotide polymorphisms (SNPs) from fifteen loci including GIPR, ADCY5, TCF7L2, VPS13C, DGKB, MADD, ADRA2A, FADS1, CRY2, SLC2A2, GLIS3, PROX1, C2CD4B, SLC30A8 and IGF1 in 6,822 Shanghai Chinese Hans comprising 3,410 type 2 diabetic patients and 3,412 normal glucose regulation subjects. MADD rs7944584 showed strong association to type 2 diabetes (p = 3.5×10−6, empirical p = 0.0002) which was not observed in the European descent populations. SNPs from GIPR, TCF7L2, CRY2, GLIS3 and SLC30A8 were also associated with type 2 diabetes (p = 0.0487∼2.0×10−8). Further adjusting age, gender and BMI as confounders found PROX1 rs340874 was associated with type 2 diabetes (p = 0.0391). SNPs from DGKB, MADD and SLC30A8 were associated with fasting glucose while PROX1 rs340874 was significantly associated with OGTT 2-h glucose (p = 0.0392∼0.0014, adjusted for age, gender and BMI), the glucose-raising allele also showed association to lower insulin secretion. IGF1 rs35767 showed significant association to both fasting and 2-h insulin levels as well as insulin secretion and sensitivity indices (p = 0.0160∼0.0035, adjusted for age, gender and BMI). Conclusions/Significance Our results indicated that SNPs from GIPR, TCF7L2, DGKB, MADD, CRY2, GLIS3, PROX1, SLC30A8 and IGF1 were associated with traits related to glucose metabolism in the Chinese population.
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van Agthoven T, Sieuwerts AM, Meijer D, Meijer-van Gelder ME, van Agthoven TLA, Sarwari R, Sleijfer S, Foekens JA, Dorssers LCJ. Selective recruitment of breast cancer anti-estrogen resistance genes and relevance for breast cancer progression and tamoxifen therapy response. Endocr Relat Cancer 2010; 17:215-30. [PMID: 19966015 DOI: 10.1677/erc-09-0062] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Although endocrine treatment of breast cancer is effective and common practice, in advanced disease the development of resistance is nearly inevitable. To get more insight into individual genes that account for resistance against hormonal agents, we have executed functional genetic screens and subsequently evaluated the clinical relevance of several identified genes with respect to tumor aggressiveness and tamoxifen resistance in estrogen receptor-positive patients. Estrogen-dependent human breast cancer cells were transduced with different retroviral cDNA expression libraries and subjected to selective cultures with various anti-estrogens. From a total of 264 resistant cell clones, 132 different genes were recovered by PCR. By applying stringent selection criteria, we identified 15 breast cancer anti-estrogen resistance (BCAR) genes individually yielding resistance. BCAR genes were recovered with differential frequencies for the diverse culture conditions and anti-estrogen drugs. Analysis of the relation of BCAR genes (EIF1, FBXL10, HRAS, NRG1, PDGFRA, PDGFRB, RAD21, and RAF1) with tamoxifen treatment in patients with advanced disease showed significant association with clinical benefit and progression-free survival for EIF1 and PDGFRA mRNA levels. Furthermore, PDGFRA and HRAS mRNA levels were significantly associated with tumor aggressiveness in lymph node-negative patients who had not received adjuvant systemic therapy. In conclusion, our functional genetic screens showed that BCAR genes differ in their ability to confer resistance towards distinct anti-estrogens. Based on the clinical relevance of several BCAR genes, further studies are warranted to characterize the underlying mechanisms, which may ultimately lead to the development of novel treatments and more individualized management of breast cancer patients.
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Canonigo-Balancio AJ, Fos C, Prod’homme T, Bécart S, Altman A. SLAT/Def6 plays a critical role in the development of Th17 cell-mediated experimental autoimmune encephalomyelitis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 183:7259-67. [PMID: 19915062 PMCID: PMC2821872 DOI: 10.4049/jimmunol.0902573] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SWAP-70-like adapter of T cells (SLAT; also known as Def6) is a novel guanine nucleotide exchange factor for Rho GTPases that has been previously shown to play a role in CD4+ T cell activation and Th1/Th2 differentiation. However, the role of SLAT/Def6 in autoimmunity and its associated Th1- and Th17-specific responses has not yet been clearly elucidated. We used a prototypical and pathologically relevant Th1/Th17-mediated autoimmune model, that is, experimental autoimmune encephalomyelitis, to assess the role of SLAT/Def6 in autoantigen-specific T cell response. We found that T cell-expressed SLAT/Def6 was critical for experimental autoimmune encephalomyelitis development and pathogenesis, as evidenced by the resistance of Def6-deficient (Def6(-/-)) mice to clinical signs of the disease associated with a lack of CNS inflammation and demyelination in myelin oligodendrocyte glycoprotein-immunized Def6(-/-) mice. Moreover, Def6 deficiency resulted in a severely diminished myelin oligodendrocyte glycoprotein-specific CD4+ T cell proliferation as well as a defect in IFN-gamma and IL-17 production in secondary lymphoid organs and the CNS. Lastly, Def6(-/-) CD4+ T cells were grossly deficient in their ability to differentiate into Th17 cells both in vitro and in vivo in a T cell-intrinsic manner. Therefore, our study establishes T cell-expressed SLAT/Def6 as a pivotal positive regulator of Th17 inflammatory responses and, thus, essential in controlling autoimmune and inflammatory diseases.
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Yamauchi J. [Signaling mechanism underlying myelination in peripheral nervous system]. SEIKAGAKU. THE JOURNAL OF JAPANESE BIOCHEMICAL SOCIETY 2009; 81:565-580. [PMID: 19697860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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91
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Makkinje A, Near RI, Infusini G, Vanden Borre P, Bloom A, Cai D, Costello CE, Lerner A. AND-34/BCAR3 regulates adhesion-dependent p130Cas serine phosphorylation and breast cancer cell growth pattern. Cell Signal 2009; 21:1423-35. [PMID: 19454314 DOI: 10.1016/j.cellsig.2009.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 05/04/2009] [Indexed: 12/27/2022]
Abstract
NSP protein family members associate with p130Cas, a focal adhesion adapter protein best known as a Src substrate that integrates adhesion-related signaling. Over-expression of AND-34/BCAR3/NSP2 (BCAR3), but not NSP1 or NSP3, induces anti-estrogen resistance in human breast cancer cell lines. BCAR3 over-expression in epithelial MCF-7 cells augments levels of a phosphorylated p130Cas species that migrates more slowly on SDS-PAGE while NSP1 and NSP3 induce modest or no phosphorylation, respectively. Conversely, reduction in BCAR3 expression in mesenchymal MDA-231 cells by inducible shRNA results in loss of such p130Cas phosphorylation. Replacement of NSP3's serine/proline-rich domain with that of AND-34/BCAR3 instills the ability to induce p130Cas phosphorylation. Phospho-amino acid analysis demonstrates that BCAR3 induces p130Cas serine phosphorylation. Mass spectrometry identified phosphorylation at p130Cas serines 139, 437 and 639. p130Cas serine phosphorylation accumulates for several hours after adhesion of MDA-231 cells to fibronectin and is dependent upon BCAR3 expression. BCAR3 knockdown alters p130Cas localization and converts MDA-231 growth to an epithelioid pattern characterized by striking cohesiveness and lack of cellular projections at colony borders. These studies demonstrate that BCAR3 regulates p130Cas serine phosphorylation that is adhesion-dependent, temporally distinct from previously well-characterized rapid Fak and Src kinase-mediated p130Cas tyrosine phosphorylation and that correlates with invasive phenotype.
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Bécart S, Balancio AJC, Charvet C, Feau S, Sedwick CE, Altman A. Tyrosine-phosphorylation-dependent translocation of the SLAT protein to the immunological synapse is required for NFAT transcription factor activation. Immunity 2008; 29:704-19. [PMID: 18976935 DOI: 10.1016/j.immuni.2008.08.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 07/08/2008] [Accepted: 08/19/2008] [Indexed: 01/07/2023]
Abstract
SWAP-70-like adaptor of T cells (SLAT) is a guanine nucleotide exchange factor for Rho GTPases that regulates the development of T helper 1 (Th1) and Th2 cell inflammatory responses by controlling the Ca(2+)-NFAT signaling pathway. However, the mechanism used by SLAT to regulate these events is unknown. Here, we report that the T cell receptor (TCR)-induced translocation of SLAT to the immunological synapse required Lck-mediated phosphorylation of two tyrosine residues located in an immunoreceptor tyrosine-based activation motif-like sequence but was independent of the SLAT PH domain. This subcellular relocalization was coupled to, and necessary for, activation of the NFAT pathway. Furthermore, membrane targeting of the SLAT Dbl-homology (catalytic) domain was sufficient to trigger TCR-mediated NFAT activation and Th1 and Th2 differentiation in a Cdc42-dependent manner. Therefore, tyrosine-phosphorylation-mediated relocalization of SLAT to the site of antigen recognition is required for SLAT to exert its pivotal role in NFAT-dependent CD4(+) T cell differentiation.
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Kanamori T, Inoue T, Sakamoto T, Gengyo-Ando K, Tsujimoto M, Mitani S, Sawa H, Aoki J, Arai H. Beta-catenin asymmetry is regulated by PLA1 and retrograde traffic in C. elegans stem cell divisions. EMBO J 2008; 27:1647-57. [PMID: 18497747 PMCID: PMC2396877 DOI: 10.1038/emboj.2008.102] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Accepted: 04/28/2008] [Indexed: 12/17/2022] Open
Abstract
Asymmetric division is an important property of stem cells. In Caenorhabditis elegans, the Wnt/beta-catenin asymmetry pathway determines the polarity of most asymmetric divisions. The Wnt signalling components such as beta-catenin localize asymmetrically to the cortex of mother cells to produce two distinct daughter cells. However, the molecular mechanism to polarize them remains to be elucidated. Here, we demonstrate that intracellular phospholipase A(1) (PLA(1)), a poorly characterized lipid-metabolizing enzyme, controls the subcellular localizations of beta-catenin in the terminal asymmetric divisions of epithelial stem cells (seam cells). In mutants of ipla-1, a single C. elegans PLA(1) gene, cortical beta-catenin is delocalized and the asymmetry of cell-fate specification is disrupted in the asymmetric divisions. ipla-1 mutant phenotypes are rescued by expression of ipla-1 in seam cells in a catalytic activity-dependent manner. Furthermore, our genetic screen utilizing ipla-1 mutants reveals that reduction of endosome-to-Golgi retrograde transport in seam cells restores normal subcellular localization of beta-catenin to ipla-1 mutants. We propose that membrane trafficking regulated by ipla-1 provides a mechanism to control the cortical asymmetry of beta-catenin.
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94
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Takahashi M, Itakura M. [Regulatory mechanisms of neurotransmitter release]. TANPAKUSHITSU KAKUSAN KOSO. PROTEIN, NUCLEIC ACID, ENZYME 2008; 53:453-458. [PMID: 21089319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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95
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Porat-Shliom N, Kloog Y, Donaldson JG. A unique platform for H-Ras signaling involving clathrin-independent endocytosis. Mol Biol Cell 2008; 19:765-75. [PMID: 18094044 PMCID: PMC2262976 DOI: 10.1091/mbc.e07-08-0841] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 11/05/2007] [Accepted: 12/07/2007] [Indexed: 11/11/2022] Open
Abstract
Trafficking of H-Ras was examined to determine whether it can enter cells through clathrin-independent endocytosis (CIE). H-Ras colocalized with the CIE cargo protein, class I major histocompatibility complex, and it was sequestered in vacuoles that formed upon expression of an active mutant of Arf6, Q67L. Activation of Ras, either through epidermal growth factor stimulation or the expression of an active mutant of Ras, G12V, induced plasma membrane ruffling and macropinocytosis, a stimulated form of CIE. Live imaging of cells expressing H-RasG12V and fluorescent protein chimeras with pleckstrin homology domains that recognize specific phosphoinositides showed that incoming macropinosomes contained phosphatidylinositol 4,5-bisphosphate (PIP(2)) and phosphatiylinositol 3,4,5-trisphosphate (PIP(3)). PIP(2) loss from the macropinosome was followed by the recruitment of Rab5, a downstream target of Ras, and then PIP(3) loss. Our studies support a model whereby Ras can signal on macropinosomes that pass through three distinct stages: PIP(2)/PIP(3), PIP(3)/Rab5, and Rab5. Vacuoles that form in cells expressing Arf6Q67L trap Ras signaling in the first stage, recruiting the active form of the Ras effectors extracellular signal-regulated kinase and protein kinase B (Akt) but not Rab5. Arf6 stimulation of macropinocytosis also involves passage through the distinct lipid phases, but recruitment of Akt is not observed.
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96
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Kikuchi T, Kubonishi S, Shibakura M, Namba N, Matsui T, Fukui Y, Tanimoto M, Katayama Y. Dock2 participates in bone marrow lympho-hematopoiesis. Biochem Biophys Res Commun 2007; 367:90-6. [PMID: 18157938 DOI: 10.1016/j.bbrc.2007.12.093] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 12/10/2007] [Indexed: 01/15/2023]
Abstract
Dock2 has been shown to be indispensable for chemotaxis of mature lymphocytes as a critical Rac activator. However, the functional expression of Dock2 in immature hematopoietic cells is unclear. In this study, we demonstrate that Dock2 is broadly expressed in bone marrow (BM) hematopoietic compartment, including hematopoietic stem/progenitor cell (HSC/HPC) fraction. Response of Dock2-/- HPCs to CXCL12 in chemotaxis and actin polymerization in vitro was impaired, although alpha4 integrin activation by CXCL12 was not altered. Myelosuppressive stress on HSCs in vivo, such as consecutive 5-FU administration and serial bone marrow transplantation, did not show hematopoietic defect in Dock2-/- mice. Long-term engraftment of transplanted Dock2-/- BM cells was severely impaired in competitive reconstitution. However, this was not intrinsic to HSCs but originated from the defective competition of Dock2-/- lymphoid precursors. These results suggest that Dock2 plays a significant role in BM lymphopoiesis, but is dispensable for HSC engraftment and self-renewal.
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97
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Potapova IA, Cohen IS, Doronin SV. Voltage-gated ion channel Kv4.3 is associated with Rap guanine nucleotide exchange factors and regulates angiotensin receptor type 1 signaling to small G-protein Rap. FEBS J 2007; 274:4375-84. [PMID: 17725712 DOI: 10.1111/j.1742-4658.2007.05966.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The voltage-gated potassium channel Kv4.3 was coexpressed with its beta-subunit Kv channel-interacting protein 2 and the angiotensin type 1 receptor in HEK-293 cells. Proteomic analysis of proteins coimmunoprecipitated with Kv4.3 revealed that Kv4.3 is associated with Rap guanine nucleotide exchange factors MR-GEF and EPAC-1. Previously, we demonstrated that Kv4.3 interacts with the angiotensin type 1 receptor in HE293 cells and cardiac myocytes. On the basis of this, we investigated the angiotensin type 1 receptor signaling to small G-proteins Ras and Rap-1 in the presence and absence of the Kv4.3-Kv channel-interacting protein 2 macromolecular complex. Ras activation was not significantly affected by coexpression of Kv4.3 and Kv channel-interacting protein 2. Ras exhibited a rapid activation-inactivation pattern with maximum activity at 2.5 min after addition of angiotensin II. In contrast, activation of Rap-1 was affected dramatically by coexpression of Kv4.3 and Kv channel-interacting protein 2 with the angiotensin type 1 receptor. In the absence of Kv4.3 and Kv channel-interacting protein 2, stimulation of the angiotensin type 1 receptor resulted in steady activation of Rap-1 that reached a plateau 25 min after addition of angiotensin II. In the presence of Kv4.3 and Kv channel-interacting protein 2, Rap-1 reaches a maximum activity 2.5 min after addition of angiotensin II and then deactivates rapidly, demonstrating a pattern of activation similar to that of Ras. Our findings show that Kv4.3 regulates angiotensin type 1 receptor signaling to the small G-protein Rap-1.
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98
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Bécart S, Charvet C, Canonigo Balancio AJ, De Trez C, Tanaka Y, Duan W, Ware C, Croft M, Altman A. SLAT regulates Th1 and Th2 inflammatory responses by controlling Ca2+/NFAT signaling. J Clin Invest 2007; 117:2164-75. [PMID: 17657315 PMCID: PMC1924495 DOI: 10.1172/jci31640] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 05/09/2007] [Indexed: 12/27/2022] Open
Abstract
SWAP-70-like adapter of T cells (SLAT) is a novel guanine nucleotide exchange factor for Rho GTPases that is upregulated in Th2 cells, but whose physiological function is unclear. We show that SLAT(-/-) mice displayed a developmental defect at one of the earliest stages of thymocyte differentiation, the double-negative 1 (DN1) stage, leading to decreased peripheral T cell numbers. SLAT(-/-) peripheral CD4(+) T cells demonstrated impaired TCR/CD28-induced proliferation and IL-2 production, which was rescued by the addition of exogenous IL-2. Importantly, SLAT(-/-) mice were grossly impaired in their ability to mount not only Th2, but also Th1-mediated lung inflammatory responses, as evidenced by reduced airway neutrophilia and eosinophilia, respectively. Levels of Th1 and Th2 cytokine in the lungs were also markedly reduced, paralleling the reduction in pulmonary inflammation. This defect in mounting Th1/Th2 responses, which was also evident in vitro, was traced to a severe reduction in Ca(2+) mobilization from ER stores, which consequently led to defective TCR/CD28-induced translocation of nuclear factor of activated T cells 1/2 (NFATc1/2). Thus, SLAT is required for thymic DN1 cell expansion, T cell activation, and Th1 and Th2 inflammatory responses.
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99
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Near RI, Zhang Y, Makkinje A, Borre PV, Lerner A. AND-34/BCAR3 differs from other NSP homologs in induction of anti-estrogen resistance, cyclin D1 promoter activation and altered breast cancer cell morphology. J Cell Physiol 2007; 212:655-65. [PMID: 17427198 PMCID: PMC2640322 DOI: 10.1002/jcp.21059] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over-expression of AND-34/BCAR3/NSP2 (BCAR3) or its binding-partner p130Cas/BCAR1 generates anti-estrogen resistance in human breast cancer lines. Here, we have compared BCAR3 to two related homologs, NSP1 and NSP3/CHAT/SHEP, with regards to expression, anti-estrogen resistance, and signaling. BCAR3 is expressed at higher levels in ERalpha-negative, mesenchymal, than in ERalpha-positive, epithelial, breast cancer cell lines. Characterization of "intermediate" epithelial-like cell lines with variable ER-alpha expression reveals that BCAR3 expression correlates with both mesenchymal and ERalpha-negative phenotypes. Levels of the BCAR3/p130Cas complex correlate more strongly with the ERalpha-negative, mesenchymal phenotype than levels of either protein alone. NSP1 and NSP3 are expressed at lower levels than BCAR3 and without correlation to ERalpha/mesenchymal status. Among NSP-transfectants, only BCAR3 transfectants induce anti-estrogen resistance and augment transcription of cyclin D1 promoter constructs. Over-expression of all homologs results in activation of Rac, Cdc42 and Akt, suggesting that these signals are insufficient to induce anti-estrogen resistance. BCAR3 but not NSP1 nor NSP3 transfectants show altered morphology, transitioning from polygonal cell groups to rounded, single cells with numerous blebs. Whereas stable over-expression of BCAR3 in MCF-7 cells does not lead to classic epithelial-to-mesenchymal transition, it does result in down-regulation of cadherin-mediated adhesion and augmentation of fibronectin expression. These studies suggest that BCAR's ability to induce anti-estrogen resistance is greater than that of other NSP homologs and may result from altered interaction of breast cancer cells with each other and the extracellular matrix.
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100
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Tanaka Y, Hamano S, Gotoh K, Murata Y, Kunisaki Y, Nishikimi A, Takii R, Kawaguchi M, Inayoshi A, Masuko S, Himeno K, Sasazuki T, Fukui Y. T helper type 2 differentiation and intracellular trafficking of the interleukin 4 receptor-α subunit controlled by the Rac activator Dock2. Nat Immunol 2007; 8:1067-75. [PMID: 17767160 DOI: 10.1038/ni1506] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Accepted: 08/02/2007] [Indexed: 11/08/2022]
Abstract
The lineage commitment of CD4+ T cells is coordinately regulated by signals through the T cell receptor and cytokine receptors, yet how these signals are integrated remains elusive. Here we find that mice lacking Dock2, a Rac activator in lymphocytes, developed allergic disease through a mechanism dependent on CD4+ T cells and the interleukin 4 receptor (IL-4R). Dock2-deficient CD4+ T cells showed impaired antigen-driven downregulation of IL-4Ralpha surface expression, resulting in sustained IL-4R signaling and excessive T helper type 2 responses. Dock2 was required for T cell receptor-mediated phosphorylation of the microtubule-destabilizing protein stathmin and for lysosomal trafficking and the degradation of IL-4Ralpha. Thus, Dock2 links T cell receptor signals to downregulation of IL-4Ralpha to control the lineage commitment of CD4+ T cells.
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