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Differential Processing (differential + processing)
Selected AbstractsWhat are you looking at?DEVELOPMENTAL SCIENCE, Issue 1 2008Infants' neural processing of an adult's object-directed eye gaze Previous research suggests that by 4 months of age infants use the eye gaze of adults to guide their attention and facilitate processing of environmental information. Here we address the question of how infants process the relation between another person and an external object. We applied an ERP paradigm to investigate the neural processes underlying the perception of the direction of an adult's eye gaze in 4-month-old infants. Infants showed differential processing of an adult's eye gaze, which was directed at a simultaneously presented object compared to non-object-directed eye gaze. This distinction was evident in two ERP components: The Negative component, reflecting attentional processes, and the positive slow wave, which is involved in memory encoding. The implications of these findings for the development of joint attention and related social cognitive functions are discussed. [source] The structure of the TGF-, latency associated peptide region determines the ability of the proprotein convertase furin to cleave TGF-,sJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2008Makoto Kusakabe Abstract The TGF-, family members are generated as latent pre-pro-polypeptides. The active mature peptides are cleaved from the latent forms by cellular proteases. TGF-,1, for instance, is predominantly processed by a substilisin-like proprotein convertase, furin. TGF-,2 has a consensus cleavage site for furin and therefore has been presumed to be cleaved by furin. However, TGF-,2 is often secreted as the latent form, which appears to be inconsistent with its postulated sensitivity to furin. We report here that both the regular (short) form of TGF-,2 and its spliced variant with an additional exon (long form) are insensitive to furin. NIH 3T3 and CHO cells were transfected with expression vectors containing the short or long form of TGF-,2 or a chimeric TGF-, consisting of the TGF-,1 LAP region, the TGF-,2 cleavage site and the TGF-,2 mature peptide. The constructs included a c- myc epitope tag in the N-terminal region of the mature peptide. The TGF-,s produced by the transfected cells were analyzed with Western blots and immunocytochemistry. The intracellular proteins harvested from these cells were incubated with furin. Furin only inefficiently cleaved both the long and short forms of TGF-,2, but efficiently processed the chimeric TGF-,. This indicates that the insensitivity of both forms of TGF-,2 to furin is a consequence of the tertiary structure of their LAP regions rather than their cleavage site. This differential processing of TGF-,1 and -,2 may be part of the mechanism that generates isoform-specific functions of the TGF-,s. J. Cell. Biochem. 103: 311,320, 2008. © 2007 Wiley-Liss, Inc. [source] Towards functional proteomics of membrane protein complexes: analysis of thylakoid membranes from Chlamydomonas reinhardtiiTHE PLANT JOURNAL, Issue 5 2001Michael Hippler Summary Functional proteomics of membrane proteins is an important tool for the understanding of protein networks in biological membranes but structural studies on this part of the proteome are limited. In this study we undertook such an approach to analyse photosynthetic thylakoid membranes isolated from wild-type and mutant strains of Chlamydomonas reinhardtii. Thylakoid membrane proteins were separated by high-resolution two-dimensional gel electrophoresis (2-DE) and analysed by immuno-blotting and mass spectrometry for the presence of membrane-spanning proteins. Our data show that light-harvesting complex proteins (LHCP), that cross the membrane with three transmembrane domains, can be separated using this method. We have identified more than 30 different LHCP spots on our gels. Mass spectrometric analysis of 2-DE separated Lhcb1 indicates that this major LHCII protein can associate with the thylakoid membrane with part of its putative transit sequence. Separation of isolated photosystem I (PSI) complexes by 2-DE revealed the presence of 18 LHCI protein spots. The use of two peptide-specific antibodies directed against LHCI subunits supports the interpretation that some of these spots represent products arising from differential processing and post-translational modifications. In addition our data indicate that the reaction centre subunit of PSI, PsaA, that possesses 11 transmembrane domains, can be separated by 2-DE. Comparison between 2-DE maps from thylakoid membrane proteins isolated from a PSI-deficient (,ycf4) and a crd1 mutant, which is conditionally reduced in PSI and LHCI under copper-deficiency, showed the presence of most of the LHCI spots in the former but their absence in the latter. Our data demonstrate that (i) hydrophobic membrane proteins like the LHCPs can be faithfully separated by 2-DE, and (ii) that high-resolution 2-DE facilitates the comparative analysis of membrane protein complexes in wild-type and mutants cells. [source] An ERP Study of Emotional Face Processing in the Adult and Infant BrainCHILD DEVELOPMENT, Issue 1 2007Jukka M. Leppänen To examine the ontogeny of emotional face processing, event-related potentials (ERPs) were recorded from adults and 7-month-old infants while viewing pictures of fearful, happy, and neutral faces. Face-sensitive ERPs at occipital,temporal scalp regions differentiated between fearful and neutral/happy faces in both adults (N170 was larger for fear) and infants (P400 was larger for fear). Behavioral measures showed no overt attentional bias toward fearful faces in adults, but in infants, the duration of the first fixation was longer for fearful than happy faces. Together, these results suggest that the neural systems underlying the differential processing of fearful and happy/neutral faces are functional early in life, and that affective factors may play an important role in modulating infants' face processing. [source] | |||||||||||||