Classification of Protein Kinases on the Basis of Both Kinase and Non-Kinase Regions

BACKGROUND: Protein phosphorylation is a generic way to regulate signal transduction pathways in all kingdoms of life. In many organisms, it is achieved by the large family of Ser/Thr/Tyr protein kinases which are traditionally classified into groups and subfamilies on the basis of the amino acid sequence of their catalytic domains. Many protein kinases are multi-domain in nature but the diversity of the accessory domains and their organization are usually not taken into account while classifying kinases into groups or subfamilies. METHODOLOGY: Here, we present an approach which considers amino acid sequences of complete gene products, in order to suggest refinements in sets of pre-classified sequences. The strategy is based on alignment-free similarity scores and iterative Area Under the Curve (AUC) computation. Similarity scores are computed by detecting common patterns between two sequences and scoring them using a substitution matrix, with a consistent normalization scheme. This allows us to handle full-length sequences, and implicitly takes into account domain diversity and domain shuffling. We quantitatively validate our approach on a subset of 212 human protein kinases. We then employ it on the complete repertoire of human protein kinases and suggest few qualitative refinements in the subfamily assignment stored in the KinG database, which is based on catalytic domains only. Based on our new measure, we delineate 37 cases of potential hybrid kinases: sequences for which classical classification based entirely on catalytic domains is inconsistent with the full-length similarity scores computed here, which implicitly consider multi-domain nature and regions outside the catalytic kinase domain. We also provide some examples of hybrid kinases of the protozoan parasite Entamoeba histolytica. CONCLUSIONS: The implicit consideration of multi-domain architectures is a valuable inclusion to complement other classification schemes. The proposed algorithm may also be employed to classify other families of enzymes with multi-domain architecture

The prion protein knockout mouse: a phenotype under challenge

The key pathogenic event in prion disease involves misfolding and aggregation of the cellular prion protein (PrP). Beyond this fundamental observation, the mechanism by which PrP misfolding in neurons leads to injury and death remains enigmatic. Prion toxicity may come about by perverting the normal function of PrP. If so, understanding the normal function of PrP may help to elucidate the molecular mechansim of prion disease. Ablation of the Prnp gene, which encodes PrP, was instrumental for determining that the continuous production of PrP is essential for replicating prion infectivity. Since the structure of PrP has not provided any hints to its possible function, and there is no obvious phenotype in PrP KO mice, studies of PrP function have often relied on intuition and serendipity. Here, we enumerate the multitude of phenotypes described in PrP deficient mice, many of which manifest themselves only upon physiological challenge. We discuss the pleiotropic phenotypes of PrP deficient mice in relation to the possible normal function of PrP. The critical question remains open: which of these phenotypes are primary effects of PrP deletion and what do they tell us about the function of PrP

High thrombotic risk is associated with higher prevalence of suboptimal stent results in patients with high bleeding risk

Abstract Funding Acknowledgements Type of funding sources: None. Background Shorter duration of dual antiplatelet therapy after drug-eluting stent implantation is required in patients with high bleeding risk (HBR) irrespective of the presence of concomitant high thrombotic risk (HTR). The prevalence of post-stent suboptimal findings in patients with HBR remains unclear. Purpose To clarify the prevalence of post-stent suboptimal findings assessed by optical coherence tomography (OCT) in patients with HBR according to the presence of HTR. Methods A total of 607 consecutive patients with stable coronary disease, who underwent OCT imaging of the culprit lesion were included. HBR was defined based on the Academic Research Consortium for High Bleeding Risk (ARC-HBR). HTR was defined as lesions with diffuse long (≧60 mm), treated with more than three stents, chronic total occlusion or diffuse long lesion (≧32 mm) in patients with diabetes mellitus. Post-stent suboptimal OCT criteria was defined as minimum stent area (MSA) &amp;lt;4.5 mm2, edge dissection and stent malapposition. Results The prevalence of HBR was 55.8%. The prevalence of HTR was significantly higher in patients with HBR than in those without HBR (35.0 vs. 26.6%, p=0.028) (Figure A). Among patients with HBR, the prevalence of post-stent suboptimal OCT criteria was significantly higher in patients with HTR than in those without HTR (86.2 vs. 64.7%, p&amp;lt;0.001), mainly due to the higher prevalence of MSA &amp;lt;4.5 mm2 (Figure B) in patients with HTR. Conclusions HTR was associated with a higher prevalence of post-stent suboptimal findings among patients with HBR. The present results may suggest the importance of optimal stenting in patients with HBR, particularly in those with concomitant HTR. </jats:sec

High sensitivity C-reactive protein is associated with vulnerable characteristics in non-culprit plaques in patients with ST-segment elevation myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: None. Background Higher level of high sensitivity C-reactive protein (hsCRP) is associated with an increased risk of recurrent cardiovascular events in patients with ST-segment elevation myocardial infarction (STEMI). However, the association between hsCRP and the characteristics of non-culprit plaques in patients with STEMI remains to be elucidated. Purpose To clarify the morphological characteristics of non-culprit plaque in patients with STEMI according to the hsCRP levels using optical coherence tomography (OCT). Methods A total of 79 non-culprit plaques in 76 consecutive patients with STEMI, who underwent OCT imaging of the non-culprit plaques in a culprit vessel were included. The characteristics of non-culprit plaques assessed by OCT were compared between the higher hsCRP group (hsCRP ≥ 0.16 mg/dL, 38 plaques in 38 patients) and the lower hsCRP group (hsCRP &amp;lt; 0.16 mg/dL, 41 plaques in 38 patients). Results The prevalence of plaque with macrophage (63.2 vs. 31.7%, p = 0.006), plaque with large lipid (maximal lipid arc &amp;gt; 180 °) (57.9 vs. 31.7%, p = 0.018), healed plaque (50.0 vs. 26.8%, p = 0.045) and cholesterol crystal (18.4 vs. 2.4%, p = 0.045) was significantly higher in the higher hsCRP group than in the lower hsCRP group (Figure). In a multivariate analysis, the higher hsCRP was independently associated with the presence of plaque with macrophage (Odds ratio [OR], 3.031; 95% confidence interval [CI]: 1.112-8.264, p = 0.030), plaque with large lipid (OR, 2.897; 95% CI: 1.122-7.478, p = 0.026) and healed plaque (OR, 2.666; 95% CI: 1.030-6.896, p = 0.040). Conclusions Higher level of hsCRP is associated with a higher prevalence of vulnerable characteristics in non-culprit plaques in patients with STEMI. The present results may partly explain the pathogenesis of an increased incidence of recurrent cardiovascular events in patients with STEMI. Abstract Figure. </jats:sec

Primary structure of the human fgr proto-oncogene product p55c-fgr.

Normal human c-fgr cDNA clones were constructed by using normal peripheral blood mononuclear cell mRNA as a template. Nucleotide sequence analysis of two such clones revealed a 1,587-base-pair-long open reading frame which predicted the primary amino acid sequence of the c-fgr translational product. Homology of this protein with the v-fgr translational product stretched from codons 128 to 516, where 32 differences among 388 codons were observed. Sequence similarity with human c-src, c-yes, and fyn translational products began at amino acid position 76 of the predicted c-fgr protein and extended nearly to its C-terminus. In contrast, the stretch of 75 amino acids at the N-terminus demonstrated a greatly reduced degree of relatedness to these same proteins. To verify the deduced amino acid sequence, antibodies were prepared against peptides representing amino- and carboxy-terminal regions of the predicted c-fgr translational product. Both antibodies specifically recognized a 55-kilodalton protein expressed in COS-1 cells transfected with a c-fgr cDNA expression plasmid. Moreover, the same protein was immunoprecipitated from an Epstein-Barr virus-infected Burkitt's lymphoma cell line which expressed c-fgr mRNA but not in its uninfected fgr mRNA-negative counterpart. These findings identified the 55-kilodalton protein as the product of the human fgr protooncogene