186,151 research outputs found
The guanine nucleotide exchange factor Ras-GRF1 directly binds microtubules via DH-PH2 mediated interaction
No full textThe guanine nucleotide exchange factor RasGRF1 directly binds microtubules via DHPH2-mediated interaction
No full textRasGRF is a family of guanine nucleotide exchange factors with dual specificity for both Ras and Rac GTPases. In this study, using mouse brain exts., we show that both RasGRF1 and RasGRF2 interact with microtubules in an in vitro microtubule assembly system and this binding is very tight. To characterize this assocn., recombinant purified proteins contg. different regions of RasGRF1 were tested for their ability to bind microtubules preassembled from pure tubulin. Only the DHPH2 tandem directly assocs. with microtubules, whereas the isolated DH or PH2 domains do not, indicating that the entire DHPH2 region is required for this assocn. The interaction occurs with high affinity (Kd ~ 2 mM) and with a stoichiometry, at satg. conditions, of one DHPH2 mols. for two tubulin dimers. Competition expts. support the hypothesis that the DHPH2 module is largely responsible for RasGRF1-microtubule interaction. In vivo colocalization of RasGRF1 and microtubules was also obsd. by fluorescence confocal microscopy in nonneuronal cells after stimulation with an oxidative stress agent and in highly differentiated neuron-like cells. Identification of microtubules as new binding partners of RasGRF1 may help to elucidate the signaling network in which RasGRF1 is involved
The neuron specific Ras-exchange factor Ras-GRF1 directly binds microtubules via DH-PH2-mediated interaction
No full textIdentification of novel RasGRF1 interacting partners by large-scale proteomic analysis
No full textThe brain-specific Ras guanine nucleotide exchange factor RasGRF1 is a protein harbouring a complex array of structural motifs. It contains a pleckstrin homology (PH1) domain, a coiled coil region (CC) and an ilimaquinone (IQ) one in addition to the catalytic Ras and Rac exchange factor domains. In this study, we used the recombinant N-terminal PH1, CC and IQ region (PHCCIQ) fused to the chitin-binding domain to isolate interacting proteins from mouse brain extracts. The use of an advanced software tool, the Pep-Miner, allowed clustering similar spectra from multiple mass spectrometry analysis, simplifying and improving the analysis of the complex peptide mixture. The most representative classes of RasGRF1-interacting proteins were ribosomal and other RNA-binding proteins, cytoskeletal proteins and proteins involved in vesicular trafficking. We confirmed the interaction of some of the identified proteins using different experimental approaches. We also demonstrated an RNA-dependent association of the PHCCIQ moiety of RasGRF1 with ribosomal protein S6 and Ras-GTPase-activating protein SH3-domain binding protein 2. In addition, we found that purified total RNA binds to the PHCCIQ fusion protein and the recombinant protein associates with poly(A)-sepharose. These data indicate that RasGRF1 can interact with different protein categories and exhibits a potential RNA-binding property
Association of the neuron specific Ras-exchange factor Ras-GRF1 with the microtubules cytoskeleton
No full textThe guanine nucleotide exchange factor RasGRF1 directly binds microtubules via DHPH2-mediated interaction
No full textThe guanine nucleotide exchange factor Ras-GRF1 directly binds microtubules via DH-PH2 mediated interaction
No full textAuthor-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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