139 research outputs found

    How current is western Marxism?

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    Osnovna teza članka glasi da je kasni Engels u razračunavanju s Marxovom kritikom političke ekonomije razvio pristup za teoriju građansko-kapitalističkog društva, unutar kojega je s jedne strane novcu, odnosno njegovoj akumulaciji u kapitalu, u potpunosti pridan konstitutivni značaj za tu društvenu formaciju, a time i intrinzična funkcija u duhu politike moći, a s druge strane u obzir uzet vrijednosno-racionalni aspekt građanskoga prava. Engels izbjegava monizam Marxova Kapitala tako da analizira sistemsku isprepletenost kapitalističkog tržišta s državnom administracijom od početka novoga vijeka do svojega vremena te pritom konstatira normativan napredak. Autorova je teza da njegova pojašnjenja unatoč svom fragmentarnom karakteru pokazuju dalekosežne veze s Weberovom teorijom novca i njegovim razumijevanjem modernog procesa racionalizacije. Autor izlaže svoju tezu kroz kontrast Engelsovog nasuprot Marxovu pristupu, te kasnijem razvoju ovih tema u radovima Lukácsa, Horkheimera, Adorna i Habermasa.The core argument of the article is that Engels in his late thought dealing with Marx’s critique of political economy developed an approach to theory of bourgeois capitalist society, Within this society, on the one hand, the money and its accumulation through capital has a constitutive role of social formation and intrinsic function of creating political power. On the other hand, this theory develops rational value aspect of bourgeois law. Engels avoids the monism of Marx’s The Capital by analyzing systemic relationship between capitalist market and state administration from the beginning of modern age to his own time and noticing a progress in this relationship. Author maintains that, despite the fragmented character of Engels’s theory, it shows a connection with Weber’s theory of money and his understanding of modern process of rationalization. Author develops his thesis by contrasting Engels’s approach to that of Marx and later development of these themes in works of Lukács, Horkheimer, Adorna and Habermasa

    Interaction of p21CDKN1A with PCNA regulates the histone acetyltransferase activity of p300 in nucleotide excision repair

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    The cell-cycle inhibitor p21CDKN1A has been suggested to directly participate in DNA repair, thanks to the interaction with PCNA. Yet, its role has remained unclear. Among proteins interacting with both p21 and PCNA, the histone acetyltransferase (HAT) p300 has been shown to participate in DNA repair. Here we report evidence indicating that p21 protein localizes and interacts with both p300 and PCNA at UV-induced DNA damage sites. The interaction between p300 and PCNA is regulated in vivo by p21. Indeed, loss of p21, or its inability to bind PCNA, results in a prolonged binding to chromatin and an increased association of p300 with PCNA, in UV-irradiated cells. Concomitantly, HAT activity of p300 is reduced after DNA damage. In vitro experiments show that inhibition of p300 HAT activity induced by PCNA is relieved by p21, which disrupts the association between recombinant p300 and PCNA. These results indicate that p21 is required during DNA repair to regulate p300 HAT activity by disrupting its interaction with PCNA

    Physical and functional interaction between DDB and XPA in nucleotide excision repair

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    Damaged DNA-binding protein (DDB), consisting of DDB1 and DDB2 subunits recognizes a wide spectrum of DNA lesions. DDB is dispensable for in vitro nucleotide excision repair (NER) reaction, but stimulates this reaction especially for cyclobutane pyrimidine dimer (CPD). Here we show that DDB directly interacts with XPA, one of core NER factors, mainly through DDB2 subunit and the amino-acid residues between 185 and 226 in XPA are important for the interaction. Interestingly, the point mutation causing the substitution from Arg-207 to Gly, which was previously identified in a XP-A revertant cell-line XP129, diminished the interaction with DDB in vitro and in vivo. In a defined system containing R207G mutant XPA and other core NER factors, DDB failed to stimulate the excision of CPD, although the mutant XPA was competent for the basal NER reaction. Moreover, in vivo experiments revealed that the mutant XPA is recruited to damaged DNA sites with much less efficiency compared with wild-type XPA and fails to support the enhancement of CPD repair by ectopic expression of DDB2 in SV40-transformed human cells. These results suggest that the physical interaction between DDB and XPA plays an important role in the DDB-mediated NER reaction

    Regulation and Role of Arabidopsis CUL4-DDB1A-DDB2 in Maintaining Genome Integrity upon UV Stress

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    Plants use the energy in sunlight for photosynthesis, but as a consequence are exposed to the toxic effect of UV radiation especially on DNA. The UV-induced lesions on DNA affect both transcription and replication and can also have mutagenic consequences. Here we investigated the regulation and the function of the recently described CUL4-DDB1-DDB2 E3 ligase in the maintenance of genome integrity upon UV-stress using the model plant Arabidopsis. Physiological, biochemical, and genetic evidences indicate that this protein complex is involved in global genome repair (GGR) of UV-induced DNA lesions. Moreover, we provide evidences for crosstalks between GGR, the plant-specific photo reactivation pathway and the RAD1-RAD10 endonucleases upon UV exposure. Finally, we report that DDB2 degradation upon UV stress depends not only on CUL4, but also on the checkpoint protein kinase Ataxia telangiectasia and Rad3-related (ATR). Interestingly, we found that DDB1A shuttles from the cytoplasm to the nucleus in an ATR-dependent manner, highlighting an upstream level of control and a novel mechanism of regulation of this E3 ligase

    PI 3 Kinase Related Kinases-Independent Proteolysis of BRCA1 Regulates Rad51 Recruitment during Genotoxic Stress in Human Cells

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    The function of BRCA1 in response to ionizing radiation, which directly generates DNA double strand breaks, has been extensively characterized. However previous investigations have produced conflicting data on mutagens that initially induce other classes of DNA adducts. Because of the fundamental and clinical importance of understanding BRCA1 function, we sought to rigorously evaluate the role of this tumor suppressor in response to diverse forms of genotoxic stress.We investigated BRCA1 stability and localization in various human cells treated with model mutagens that trigger different DNA damage signaling pathways. We established that, unlike ionizing radiation, either UVC or methylmethanesulfonate (MMS) (generating bulky DNA adducts or alkylated bases respectively) induces a transient downregulation of BRCA1 protein which is neither prevented nor enhanced by inhibition of PIKKs. Moreover, we found that the proteasome mediates early degradation of BRCA1, BARD1, BACH1, and Rad52 implying that critical components of the homologous recombination machinery need to be functionally abrogated as part of the early response to UV or MMS. Significantly, we found that inhibition of BRCA1/BARD1 downregulation is accompanied by the unscheduled recruitment of both proteins to chromatin along with Rad51. Consistently, treatment of cells with MMS engendered complete disassembly of Rad51 from pre-formed ionizing radiation-induced foci. Following the initial phase of BRCA1/BARD1 downregulation, we found that the recovery of these proteins in foci coincides with the formation of RPA and Rad51 foci. This indicates that homologous recombination is reactivated at later stage of the cellular response to MMS, most likely to repair DSBs generated by replication blocks.Taken together our results demonstrate that (i) the stabilities of BRCA1/BARD1 complexes are regulated in a mutagen-specific manner, and (ii) indicate the existence of mechanisms that may be required to prevent the simultaneous recruitment of conflicting signaling pathways to sites of DNA damage

    John Searle

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