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  • 1
    Publication Date: 2013-10-04
    Description: The primary cilium is a microtubule-based organelle that functions in sensory and signalling pathways. Defects in ciliogenesis can lead to a group of genetic syndromes known as ciliopathies. However, the regulatory mechanisms of primary ciliogenesis in normal and cancer cells are incompletely understood. Here we demonstrate that autophagic degradation of a ciliopathy protein, OFD1 (oral-facial-digital syndrome 1), at centriolar satellites promotes primary cilium biogenesis. Autophagy is a catabolic pathway in which cytosol, damaged organelles and protein aggregates are engulfed in autophagosomes and delivered to lysosomes for destruction. We show that the population of OFD1 at the centriolar satellites is rapidly degraded by autophagy upon serum starvation. In autophagy-deficient Atg5 or Atg3 null mouse embryonic fibroblasts, OFD1 accumulates at centriolar satellites, leading to fewer and shorter primary cilia and a defective recruitment of BBS4 (Bardet-Biedl syndrome 4) to cilia. These defects are fully rescued by OFD1 partial knockdown that reduces the population of OFD1 at centriolar satellites. More strikingly, OFD1 depletion at centriolar satellites promotes cilia formation in both cycling cells and transformed breast cancer MCF7 cells that normally do not form cilia. This work reveals that removal of OFD1 by autophagy at centriolar satellites represents a general mechanism to promote ciliogenesis in mammalian cells. These findings define a newly recognized role of autophagy in organelle biogenesis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4075283/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4075283/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tang, Zaiming -- Lin, Mary Grace -- Stowe, Timothy Richard -- Chen, She -- Zhu, Muyuan -- Stearns, Tim -- Franco, Brunella -- Zhong, Qing -- CA133228/CA/NCI NIH HHS/ -- R01 CA133228/CA/NCI NIH HHS/ -- TGM11CB3/Telethon/Italy -- England -- Nature. 2013 Oct 10;502(7470):254-7. doi: 10.1038/nature12606. Epub 2013 Oct 2.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Autophagy Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24089205" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Autophagy/genetics ; Cell Line ; Centrioles/*metabolism ; Cilia/genetics/metabolism/*physiology ; Gene Knockdown Techniques ; HEK293 Cells ; Humans ; MCF-7 Cells ; Mice ; Protein Transport ; Proteins/genetics/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2015-02-18
    Description: Autophagy, an important catabolic pathway implicated in a broad spectrum of human diseases, begins by forming double membrane autophagosomes that engulf cytosolic cargo and ends by fusing autophagosomes with lysosomes for degradation. Membrane fusion activity is required for early biogenesis of autophagosomes and late degradation in lysosomes. However, the key regulatory mechanisms of autophagic membrane tethering and fusion remain largely unknown. Here we report that ATG14 (also known as beclin-1-associated autophagy-related key regulator (Barkor) or ATG14L), an essential autophagy-specific regulator of the class III phosphatidylinositol 3-kinase complex, promotes membrane tethering of protein-free liposomes, and enhances hemifusion and full fusion of proteoliposomes reconstituted with the target (t)-SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) syntaxin 17 (STX17) and SNAP29, and the vesicle (v)-SNARE VAMP8 (vesicle-associated membrane protein 8). ATG14 binds to the SNARE core domain of STX17 through its coiled-coil domain, and stabilizes the STX17-SNAP29 binary t-SNARE complex on autophagosomes. The STX17 binding, membrane tethering and fusion-enhancing activities of ATG14 require its homo-oligomerization by cysteine repeats. In ATG14 homo-oligomerization-defective cells, autophagosomes still efficiently form but their fusion with endolysosomes is blocked. Recombinant ATG14 homo-oligomerization mutants also completely lose their ability to promote membrane tethering and to enhance SNARE-mediated fusion in vitro. Taken together, our data suggest an autophagy-specific membrane fusion mechanism in which oligomeric ATG14 directly binds to STX17-SNAP29 binary t-SNARE complex on autophagosomes and primes it for VAMP8 interaction to promote autophagosome-endolysosome fusion.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4442024/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4442024/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Diao, Jiajie -- Liu, Rong -- Rong, Yueguang -- Zhao, Minglei -- Zhang, Jing -- Lai, Ying -- Zhou, Qiangjun -- Wilz, Livia M -- Li, Jianxu -- Vivona, Sandro -- Pfuetzner, Richard A -- Brunger, Axel T -- Zhong, Qing -- 5P30CA142543/CA/NCI NIH HHS/ -- P41 GM103403/GM/NIGMS NIH HHS/ -- R01 CA133228/CA/NCI NIH HHS/ -- R01 R37-MH63105/MH/NIMH NIH HHS/ -- R37 MH063105/MH/NIMH NIH HHS/ -- T32 GM007232/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2015 Apr 23;520(7548):563-6. doi: 10.1038/nature14147. Epub 2015 Feb 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, USA [2] Department of Structural Biology, Stanford University, Stanford, California 94305, USA [3] Department of Photon Science, Stanford University, Stanford, California 94305, USA [4] Department of Neurology and Neurological Sciences, Stanford University, Stanford, California 94305, USA [5] Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, USA. ; 1] Center for Autophagy Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA [2] Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA [3] College of Food Science &Nutritional Engineering, China Agricultural University, Beijing 100083, China. ; 1] Center for Autophagy Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA [2] Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA. ; Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25686604" target="_blank"〉PubMed〈/a〉
    Keywords: Adaptor Proteins, Vesicular Transport/*chemistry/*metabolism ; *Autophagy ; Endosomes/*metabolism ; HEK293 Cells ; HeLa Cells ; Humans ; Lysosomes/*metabolism ; *Membrane Fusion ; Phagosomes/chemistry/*metabolism ; Protein Binding ; Protein Multimerization ; Protein Structure, Tertiary ; Qa-SNARE Proteins/metabolism ; Qb-SNARE Proteins/metabolism ; Qc-SNARE Proteins/metabolism ; R-SNARE Proteins/metabolism ; SNARE Proteins/chemistry/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Abstract: Over the past two decades, the molecular machinery that underlies autophagic responses has been characterized with ever increasing precision in multiple model organisms. Moreover, it has become clear that autophagy and autophagy-related processes have profound implications for human pathophysiology. However, considerable confusion persists about the use of appropriate terms to indicate specific types of autophagy and some components of the autophagy machinery, which may have detrimental effects on the expansion of the field. Driven by the overt recognition of such a potential obstacle, a panel of leading experts in the field attempts here to define several autophagy-related terms based on specific biochemical features. The ultimate objective of this collaborative exchange is to formulate recommendations that facilitate the dissemination of knowledge within and outside the field of autophagy research.
    Type of Publication: Journal article published
    PubMed ID: 28596378
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  • 4
    Abstract: Cleavage of transfer (t)RNA and ribosomal (r)RNA are critical and conserved steps of translational control for cells to overcome varied environmental stresses. However, enzymes that are responsible for this event have not been fully identified in high eukaryotes. Here, we report a mammalian tRNA/rRNA-targeting endoribonuclease: SLFN13, a member of the Schlafen family. Structural study reveals a unique pseudo-dimeric U-pillow-shaped architecture of the SLFN13 N'-domain that may clamp base-paired RNAs. SLFN13 is able to digest tRNAs and rRNAs in vitro, and the endonucleolytic cleavage dissevers 11 nucleotides from the 3'-terminus of tRNA at the acceptor stem. The cytoplasmically localised SLFN13 inhibits protein synthesis in 293T cells. Moreover, SLFN13 restricts HIV replication in a nucleolytic activity-dependent manner. According to these observations, we term SLFN13 RNase S13. Our study provides insights into the modulation of translational machinery in high eukaryotes, and sheds light on the functional mechanisms of the Schlafen family.
    Type of Publication: Journal article published
    PubMed ID: 29563550
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  • 5
    Publication Date: 2018-06-05
    Description: Prevalence of circulating immunocomplexes (ICs) strongly correlates with rheumatoid arthritis (RA) in humans. Deposits of IgG-ICs are abundant in affected joints of patients, yet molecular mechanisms for the pathogenic roles of such ICs are not fully understood. In this study, we present evidence that IgG-ICs precipitated from RA sera sensitized human monocytes for a long-lasting inflammatory functional state, characterized by a strong TNF-α response to cellular proteins representing damage-associated molecular patterns and microbe-derived pathogen-associated molecular patterns. Importantly, plate-coated human IgG (a mimic of deposited IC without Ag restriction) exhibited a similarly robust ability of monocyte sensitization in vitro. The plate-coated human IgG–induced functional programming is accompanied by transcriptomic and epigenetic modification of various inflammatory cytokines and negative regulator genes. Moreover, macrophages freshly isolated from synovia of patients with RA, but not sera-negative arthropathy, displayed a signature gene expression profile highly similar to that of IC-sensitized human monocytes, indicative of historical priming events by IgG-ICs in vivo. Thus, the ability of IgG-ICs to drive sustainable functional sensitization/reprogramming of monocytes and macrophages toward inflammation may render them key players in the development of RA.
    Print ISSN: 0022-1767
    Electronic ISSN: 1550-6606
    Topics: Medicine
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  • 6
    Publication Date: 2018-02-02
    Description: Purpose: Nasopharyngeal carcinoma (NPC) is the most common head and neck cancer in Southeast Asia. Because local recurrence and distant metastasis are still the main causes of NPC treatment failure, it is urgent to identify new tumor markers and therapeutic targets for advanced NPC. Experimental Design: RNA sequencing (RNA-seq) was applied to look for interchromosome translocation in NPC. PCR, FISH, and immunoprecipitation were used to examine the fusion gene expression at RNA, DNA, and protein levels in NPC biopsies. MTT assay, colony formation assay, sphere formation assay, co-immunoprecipitation, chromatin immunoprecipitation assay, and in vivo chemoresistance assay were applied to explore the function of RARS-MAD1L1 in NPC. Results: We demonstrated that RARS-MAD1L1 was present in 10.03% (35/349) primary NPC biopsies and 10.7% (9/84) in head and neck cancer (HNC) samples. RARS-MAD1L1 overexpression increased cell proliferation, colony formation, and tumorigenicity in vitro , and the silencing of endogenous RARS-MAD1L1 reduced cancer cell growth and colony formation in vitro . In addition, RARS-MAD1L1 increased the side population (SP) ratio and induced chemo- and radioresistance. Furthermore RARS-MAD1L1 interacted with AIMP2, which resulted in activation of FUBP1/c-Myc pathway. The silencing of FUBP1 or the administration of a c-Myc inhibitor abrogated the cancer stem cell (CSC)-like characteristics induced by RARS-MAD1L1. The expression of c-Myc and ABCG2 was higher in RARS-MAD1L1 –positive HNC samples than in negative samples. Conclusions: Our findings indicate that RARS-MAD1L1 might contribute to tumorigenesis, CSC-like properties, and therapeutic resistance, at least in part, through the FUBP1/c-Myc axis, implying that RARS-MAD1L1 might serve as an attractive target for therapeutic intervention for NPC. Clin Cancer Res; 24(3); 659–73. ©2017 AACR .
    Print ISSN: 1078-0432
    Electronic ISSN: 1557-3265
    Topics: Medicine
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  • 7
    ISSN: 1432-1912
    Keywords: Ca2+ ; Ca2+ channels ; Ca2+ channel antagonists ; 1,4-Dihydropyridines ; [3H]PN 200-110
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The Ca2+ channel antagonistic potencies of tiamdipine [2-(2-aminoethylthio)methyl-3-carboethoxy-5-carbomethoxy-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine] and nifedipine [2,6-dimethyl-3,5-dicarbomethoxy-4-(2nitrophenyl)-1,4-dihydropyridine] analogs bearing phenyl ring substituents were studied using pharmacologic and radioligand binding techniques. Additionally, analogs of tiamdipine possessing (2-aminoethylthio)methyl-, (2-acetamidoethylthio)methyl-and (2-pyrrolidinylmethylthio)methyl-groups at the C2 position of the 1,4-dihydropyridine ring have been studied. Tiamdipine and nifedipine analogs inhibited K+-induced contractile responses in rat tail artery. IC50 values of 4-phenyl ring substituted 2-(2-aminoethylthio)methyl tiamdipine analogs ranged from 10−7 mol/l to 10−8 mol/l. However, the corresponding 4-phenyl ring substituted nifedipine analogs covered a wider range of potency from 10−6 mol/l to 10−9 mol/l. K, values of the corresponding tiamdipine analogs for the inhibition of specific [3H]PN 200-110 [( I- ) [3H]isopropyl-4-(2,1,3-benzoxadiazol-4-yl)-1,4-dihydro-5-methoxycarbonyl-2,6-dimethyl-3-pyridinecarboxylate] binding-ranged from 10−7 mol/l to 10−9 mol/l in guinea pig ileal and rat heart membranes and rat brain synaptosomes. The two stereoisomers of tiamdipine and its analog 2-(2acetamidoethylthio)methyl-3-carboethoxy-5-carbomethoxy-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine, and the four stereoisomers of 2-(2-pyrrolidinylmethylthio)methyl-3carboethoxy-5-carbomethoxy-6-methyl-4-(3-nitrophenyl)1,4-dihydropyridine showed high stereoselectivity ratios of approximately (−)/(+) = 100 and 1000 in pharmacologic and binding experiments, respectively. The inhibitory actions of 2-(2-aminoethylthio)methyltiamdipine analogs against K+-induced contractile responses in rat tail artery developed very slowly requiring at least 2 h for maximum effect. The recoveries of response to K+ depolarization were also correspondingly slow. However, recovery was greatly accelerated by the presence of the 1,4-dihydropyridine activator Bay K 8644 [2,6-dimethyl-3carbomethoxy-5-nitro-4-(2-trifluoromethyl)-1,4-dihydropyridine, 5 × 10−6 mol/l] immediately prior to the K+ challenge. The 2-(2-acetamidoethylthio)methyl tiamdipine derivative and nifedipine produced maximum inhibitory effects within 10 min, and responses recovered rapidly upon washing. The slow kinetics of onset and offset of action of the tiamdipine analogs and the reduced effects of 4-phenyl substitution relative to agents of the nifedipine series suggest that these two series of 1,4-dihydropyridines exhibit different modes of interaction with the Ca2+ channel. At least part of this difference is to be attributed to the presence of a charged group in the basic tiamdipine series. Trapping of these agents within the membrane phase likely contributes to their observed slow kinetics of action.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 4644-4647 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The dynamics of the interaction of the Rydberg E(1Σ+) state and the valence state V(1Σ+) of HBr and DBr were investigated using a reflectron time-of-flight mass spectrometer coupled with a femtosecond laser system. Interrogation of the state formed by the avoided crossing of the Rydberg and valence states revealed dynamic behavior that was different for the two isotopes. Pump–probe experiments on HBr showed no change in the lifetime over the range of pump wavelengths of 256.7–254.7 nm. However, the lifetime of DBr decreased as the pump wavelength was tuned bluer. Tunneling is involved in the evolution of the population in photoexcited Rydberg state to the ion-pair state. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 192-196 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Because of the dispute in the literature over the dissociation rate and energy partitioning of the acetone molecule upon photoexcitation to the S1 state (π*←n) and 3s Rydberg state (3s←n), we have remeasured the lifetime of acetone (also d6-acetone) on the S1 and 3s surfaces by a femtosecond time-resolved multiphoton ionization technique, coupled with a reflectron time-of-flight mass spectrometer. The measured dissociation rate of acetone on the S1 surface is prompt, and the acetyl radical is long lived. The lifetime of acetone on the 3s surface is measured to be 3.2±0.4 ps (6.0±0.5 ps for d6-acetone). The dissociation rate of acetyl is approximately 1.7 ps (2.5 ps for d3-acetyl) from the curve fitting. This agrees well with the Rice–Ramsperger–Kassel–Marcus theory predicted lifetime of 1.0 ps (1.9 ps for d3-acetyl) when the internal excitation energy of the acetyl radical is treated by a statistical-adiabatic-impulsive model. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0009-2614
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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