2,061 research outputs found
Association of Rap1a and Rap1b proteins with late endocytic/phagocytic compartments
No full textAmong the small GTPases of the Ras family, Rap proteins exhibit the highest homology with p21Ras. The four Rap proteins so far identified constitute two subgroups, comprising the Rap1(A,B) and the Rap2(A,B) proteins. The intracellular location of Rap1A, Rap1B and Rap2A proteins was investigated in mammalian cells by confocal immunofluorescence microscopy. Using a specific anti-Rap1 affinity-purified antibody, both Rap1A and Rap1B proteins were localized to late endocytic compartments (late endosomes/lysosomes) in fibroblasts. The localization of the Rap1A and B proteins transiently overexpressed with the vaccinia T7 system was identical to that observed for endogenous Rap1 proteins. In contrast, epitope-tagged Rap2A protein colocalized with several markers of the Golgi complex, thus indicating that its site of function was distinct from that of Rap1A. In addition, morphological and subcellular fractionation studies provided evidence for the association of Rap1 proteins with phagosomes displaying biochemical features of late endocytic structures in J774 macrophages. Thus, the localization of Rap1A and Rap1B implicates their involvement in late endocytic/phagocytic processe
The small GTPase rab5 functions as a regulatory factor in the early endocytic pathway
No full textWe have investigated the in vivo functional role of rab5, a small GTPase associated with the plasma membrane and early endosomes. Wild-type rab5 or rab5-ile133, a mutant protein defective in GTP binding, was overexpressed in baby hamster kidney cells. In cells expressing the rab5ile 133 protein, the rate of endocytosis was decreased by 50% compared with normal, while the rate of recycling was not significantly affected. The morphology of early endosomes was also drastically changed by the mutant protein, which induced accumulation of small tubules and vesicles at the periphery of the cell. Surprisingly, overexpression of wild-type rab5 accelerated the uptake of endocytic markers and led to the appearance of atypically large early endosomes. We conclude that rab5 is a rate-limiting component of the machinery regulating the kinetics of membrane traffic in the early endocytic pathway
Meeting with the Hebrew author Elias Hurwitz
No full textWhite paper; handpainted; on the reverse of Luftwaffe uniform pattern. Digitized posters are related to the activities of Jewish displaced persons drawn from the Records of Displaced Persons Camps and Centers in Germany (RG 294.2) Italy (RG 294.3) and Austria (RG 294.4) held by YIVO Archives. Please consult the historical note for those record groups for further information.Digital ImageDigital finding aid available
The GTPase-Activating Protein GRAF1 regulates the CLIC/GEEC Endocytic Pathway
No full textClathrin-independent endocytosis is an umbrella term for a variety of endocytic pathways that internalize numerous cargoes independently of the canonical coat protein Clathrin [1, 2]
Measurement of associated W+ charm production in pp collisions at √s=7 TeV
No full textOpen Access, Copyright CERN, for the benefit of the CMS Collaboration.Measurements are presented of the associated production of a W boson and a charm-quark jet (W + c) in pp collisions at a center-of-mass energy of 7 TeV. The analysis is conducted with a data sample corresponding to a total integrated luminosity of 5 fb−1, collected by the CMS detector at the LHC. W boson candidates are identified by their decay into a charged lepton (muon or electron) and a neutrino. The W + c measurements are performed for charm-quark jets in the kinematic region p jet T > 25 GeV, |ηjet| 25 GeV) and σ(pp → W + c + X)× B (W → ℓν) = 84.1 ± 2.0 (stat.) ± 4.9 (syst.) pb ( p ℓ T > 35 GeV), and the cross section ratios σ(pp → W+ + c ¯ + X)/σ(pp → W− + c + X) = 0.954 ± 0.025 (stat.) ± 0.004 (syst.) ( p ℓ T > 25 GeV) and σ(pp → W+ + c ¯ + X)/σ(pp → W− + c + X) = 0.938 ± 0.019 (stat.) ± 0.006 (syst.) ( p ℓ T > 35 GeV). Cross sections and cross section ratios are also measured differentially with respect to the absolute value of the pseudorapidity of the lepton from the W-boson decay. These are the first measurements from the LHC directly sensitive to the strange quark and antiquark content of the proton. Results are compared with theoretical predictions and are consistent with the predictions based on global fits of parton distribution functions
Understanding parton evolution in matter from renormalization group analysis
No full textWe perform a renormalization group (RG) analysis of collinear hadron
production in deep inelastic scattering on nuclei. We consider the limit where
the parent parton energy is large, while the medium opacity
remains small. We identify the fixed order and leading
enhanced medium contributions to the semi-inclusive cross sections and derive
RG equations that resum multiple emissions near the endpoints of the splitting
functions at first order in opacity. These evolution equations treat the same
type of radiation enhancement in matter as the modified
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi approach, but differ in the way one
regulates the collinear divergences. They provide a unique analytic insight
into the problem of resummation and a faster and more efficient path to
phenomenology. The new RG evolution framework is applied to study fragmentation
in A reactions.Comment: Accepted by Phys. Lett. B., 7 pages, 2 figure
Understanding parton evolution in matter from renormalization group analysis
No full textWe perform a renormalization group (RG) analysis of collinear hadron production in deep inelastic scattering on nuclei. We consider the limit where the parent parton energy E is large, while the medium opacity L/λg remains small. We identify the fixed order and leading ln(E/ξ2L) enhanced medium contributions to the semi-inclusive cross sections and derive RG equations that resum multiple emissions near the endpoints of the splitting functions at first order in opacity. These evolution equations treat the same type of radiation enhancement in matter as the modified Dokshitzer-Gribov-Lipatov-Altarelli-Parisi approach, but differ in the way one regulates the collinear divergences. They provide a unique analytic insight into the problem of resummation and a faster and more efficient path to phenomenology. The new RG evolution framework is applied to study fragmentation in eA reactions
Obituary announcement about author and labor activist Sh. Mendelson
No full textBrown paper; handpainted. Digitized posters are related to the activities of Jewish displaced persons drawn from the Records of Displaced Persons Camps and Centers in Germany (RG 294.2) Italy (RG 294.3) and Austria (RG 294.4) held by YIVO Archives. Please consult the historical note for those record groups for further information.Digital ImageDigital finding aid available
NNLO global parton analysis
No full textWe perform a NNLO (and a LO) global parton analysis in which we include the new precise data for deep inelastic scattering from HERA and for inclusive jet production at the Tevatron, together with the improved knowledge of the three-loop splitting functions. The results are compared with our recent NLO analyses. The LO fit produces significantly worse results in general, but gives a surprisingly good fit to the Tevatron high-E_T jet data. For the approximate NNLO analysis we notice a slight improvement in the quality of the global fit, and find that the partons are changed by up to 10% at Q^2=10 GeV^2, in particular in the x<0.01 regime.We perform a NNLO (and a LO) global parton analysis in which we include the new precise data for deep inelastic scattering from HERA and for inclusive jet production at the Tevatron, together with the improved knowledge of the three-loop splitting functions. The results are compared with our recent NLO analyses. The LO fit produces significantly worse results in general, but gives a surprisingly good fit to the Tevatron high-E_T jet data. For the approximate NNLO analysis we notice a slight improvement in the quality of the global fit, and find that the partons are changed by up to 10% at Q^2=10 GeV^2$, in particular in the x<0.01 regime.We perform a NNLO (and a LO) global parton analysis in which we include the new precise data for deep inelastic scattering from HERA and for inclusive jet production at the Tevatron, together with the improved knowledge of the three-loop splitting functions. The results are compared with our recent NLO analyses. The LO fit produces significantly worse results in general, but gives a surprisingly good fit to the Tevatron high- E T jet data. For the approximate NNLO analysis we notice a slight improvement in the quality of the global fit, and find that the partons are changed by up to 10% at Q 2 =10 GeV 2 , in particular in the x <0.01 regime
Sweeping has no effect on renormalized turbulent viscosity
No full textWe perform renormalization group analysis (RG) of the Navier-Stokes equation in the presence of constant mean velocity field , and show that the renormalized viscosity is unaffected by , thus negating the ``sweeping effect", proposed by Kraichnan [Phys. Fluids {\bf 7}, 1723 (1964)] using random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for and differ from each other, but the renormalized viscosity for the two cases are the same. Our numerical results are consistent with the RG calculations
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