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C-terminal Peptide (c-terminal + peptide)
Selected AbstractsAntiproliferative activity of CCN3: Involvement of the C-terminal module and post-translational regulation,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2007A.M. Bleau Abstract Previous work had suggested that recombinant CCN3 was partially inhibiting cell proliferation. Here we show that native CCN3 protein secreted into the conditioned medium of glioma transfected cells indeed induces a reduction in cell proliferation. Large amounts of CCN3 are shown to accumulate both cytoplasmically and extracellularly as cells reach high density, therefore highlighting new aspects on how cell growth may be regulated by CCN proteins. Evidence is presented establishing that the amount of CCN3 secreted into cell culture medium is regulated by post-translational proteolysis. As a consequence, the production of CCN3 varies throughout the cell cycle and CCN3 accumulates at the G2/M transition of the cycle. We also show that CCN3-induced inhibition of cell growth can be partially reversed by specific antibodies raised against a C-terminal peptide of CCN3. The use of several clones expressing various portions of CCN3 established that the CT module of CCN3 is sufficient to induce cell growth inhibition. J. Cell. Biochem. 101: 1475,1491, 2007. © 2007 Wiley-Liss, Inc. [source] Selective enhancement of the activity of C-terminally truncated, but not intact, acetylcholinesteraseJOURNAL OF NEUROCHEMISTRY, Issue 1 2008Martina Zimmermann Abstract Acetylcholinesterase (AChE) is one of the fastest enzymes approaching the catalytic limit of enzyme activity. The enzyme is involved in the terminal breakdown of the neurotransmitter acetylcholine, but non-enzymatic roles have also been described for the entire AChE molecule and its isolated C-terminal sequences. These non-cholinergic functions have been attributed to both the developmental and degenerative situation: the major form of AChE present in these conditions is monomeric. Moreover, AChE has been shown to lose its typical characteristic of substrate inhibition in both development and degeneration. This study characterizes a form of AChE truncated after amino acid 548 (T548-AChE), whose truncation site is homologue to that of a physiological form of T-AChE detected in fetal bovine serum that has lost its C-terminal moiety supposedly due to proteolytic cleavage. Peptide sequences covered by this C-terminal sequence have been shown to be crucially involved in both developmental and degenerative mechanisms in vitro. Numerous studies have addressed the structure,function relationship of the AChE C-terminus with T548-AChE representing one of the most frequently studied forms of truncated AChE. In this study, we provide new insight into the understanding of the functional characteristics that T548-AChE acquires in solution: T548-AChE is incubated with agents of varying net charge and molecular weight. Together with kinetic studies and an analysis of different molecular forms and aggregation states of T548-AChE, we show that the enzymatic activity of T548-AChE, an enzyme verging at its catalytic limit is, nonetheless, apparently enhanced by up to 800%. We demonstrate, first, how the activity of T548-AChE can be enhanced through agents that contain highly positive charged moieties. Moreover, the un-competitive mechanism of activity enhancement most likely involves the peripheral anionic site of AChE that is reflected in delayed substrate inhibition being observed for activity enhanced T548-AChE. The data provides evidence towards a mechanistic and functional link between the form of AChE unique to both development and degeneration and a C-terminal peptide of T-AChE acting under those conditions. [source] Distinct C-terminus of the B subunit of factor XIII in a population-associated major phenotype: the first case of complete allele-specific alternative splicing products in the coagulation and fibrinolytic systemsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2009H. IWATA Summary.,Objectives: The purpose of this study was to elucidate the molecular bases of the heterogeneity of the B subunit of coagulation factor XIII (FXIII-B), classified by isoelectric focusing into its three population-associated major phenotypes. Methods and Results: By genetic sequencing and polymerase chain reaction (PCR),restriction fragment length polymorphism analyses, a C-to-G change was identified in intron K for the Asian-associated major phenotype FXIII-B*3. A transcript containing the novel exon XII, was detected by reverse transcription PCR using hepatocyte cell lines with this allele. The exclusive existence of a novel C-terminal peptide in a homozygote of FXIII-B*3 was also detected by matrix-assisted laser-desorption ionization time of flight mass spectrometry. The FXIII-B*3 isoform had a C-terminus 15 residues longer than the other isoforms, containing two additional basic amino acids and one extra acidic amino acid. Accordingly, the C-to-G nucleotide substitution created an efficient splice acceptor AG dinucleotide, which resulted in allele-specific alternative splicing in intron K. When compared with FXIII-B*1, the third major phenotype, FXIII-B*2, had an A-to-G change in exon III, converting His95 to Arg, and a rare phenotype, FXIII-B*4, had an A-to-T change in exon VII, converting Glu368 to Val. Conclusions: We found an extremely rare event of complete allele-specific alternative splicing for FXIII-B. The FXIII-B*3 isoform had a distinct C-terminal peptide, while the FXIII-B*2 and FXIII-B*4 isoforms had His95 to Arg and Glu368 to Val substitutions, respectively, which led to differential isoelectric points of these isoforms. Such variations in the amino acid sequence of FXIII-B may have profound effects on its structure,function relationship, plasma FXIII levels, and disease susceptibility. [source] Molecular Modeling of Meta II RhodopsinMOLECULAR INFORMATICS, Issue 2 2006lusarz Abstract A model believed to be representative for activated class A G protein-coupled receptors is proposed. It consists of rhodopsin and the transducin , C-terminal peptide [Gt,(338,350)] docked to it. The model utilizes the resolved interactions/distances, found to be essential in the activated rhodopsin (RD*) and the structure of Gt,(338,350) that is known to stabilize RD*. Long-term molecular dynamics (14.8,ns) in fully hydrated lipid bilayer model is applied to the system to refine and verify conformational changes in rhodopsin itself and the structure of the complex. A concomitant role of Gt, and Gt, C-termini in stabilizing RD* could possibly be resolved assuming a receptor dimer as a requisite for G protein activation. [source] Solution structure of GOPC PDZ domain and its interaction with the C-terminal motif of neuroliginPROTEIN SCIENCE, Issue 9 2006Xiang Li Abstract GOPC (Golgi-associated PDZ and coiled-coil motif-containing protein) represents a PDZ domain-containing protein associated with the Golgi apparatus, which plays important roles in vesicular trafficking in secretory and endocytic pathways. GOPC interacts with many other proteins, such as the Wnt receptors Frizzled 8 and neuroligin via its PDZ domain. Neuroligin is a neural cell-adhesion molecule of the post-synapse, which binds to the presynapse molecule neurexin to form a heterotypic intercellular junction. Here we report the solution structure of the GOPC PDZ domain by NMR. Our results show that it is a canonical class I PDZ domain, which contains two ,-helices and six ,-strands. Using chemical shift perturbation experiments, we further studied the binding properties of the GOPC PDZ domain with the C-terminal motif of neuroligin. The observations showed that the ensemble of the interaction belongs to fast exchange with low affinity. The 3D model of the GOPC PDZ domain/neuroligin C-terminal peptide complex was constructed with the aid of the molecular dynamics simulation method. Our discoveries provide insight into the specific interaction of the GOPC PDZ domain with the C-terminal peptide of Nlg and also provide a general insight about the possible binding mode of the interaction of Nlg with other PDZ domain-containing proteins. [source] Increases in collagen type I synthesis in asthma: the role of eosinophils and transforming growth factor-b,CLINICAL & EXPERIMENTAL ALLERGY, Issue 6 2002A. Nomura Summary Background Collagen type I is one of the major deposits in thickening of the reticular basement membrane of asthma. Objective and Methods In this study, we assessed turnover of collagen type I in asthma by measuring procollagen type I C-terminal peptide (PICP) and collagen type I C-terminal telopeptide (ICTP) in induced sputum. Results PICP but not ICTP was found to be significantly higher in asthma subjects than in normal volunteers (P < 0.05). In asthma, PICP was inversely correlated with %FEV1.0 (r = ,0.539), and its levels significantly increased upon exacerbation (P < 0.05), indicating that collagen synthesis increases during asthma exacerbation. Additionally, PICP was found to significantly correlate with eosinophil counts in sputum (r = 0.539), indicating that eosinophils stimulate collagen turnover. Because eosinophils can produce TGF-,, a potent stimulator of collagen synthesis, we immunocytochemically examined TGF-,-positive cells in sputum. TGF-,-positive cells significantly correlated with eosinophil counts (r = 0.811) and PICP (r = 0.569), suggesting that TGF-, released from eosinophils is involved in collagen synthesis. Conclusions The results of the present study suggest that collagen synthesis is stimulated in asthmatic airways by eosinophils through TGF-,, while collagen degradation is not, and that PICP in sputum can act as a new marker for airway inflammation in asthma. [source] Redox-regulated affinity of the third PDZ domain in the phosphotyrosine phosphatase PTP-BL for cysteine-containing target peptidesFEBS JOURNAL, Issue 13 2005Lieke C. J. Van Den Berk PDZ domains are protein,protein interaction modules that are crucial for the assembly of structural and signalling complexes. They specifically bind to short C-terminal peptides and occasionally to internal sequences that structurally resemble such peptide termini. The binding of PDZ domains is dominated by the residues at the P0 and P,2 position within these C-terminal targets, but other residues are also important in determining specificity. In this study, we analysed the binding specificity of the third PDZ domain of protein tyrosine phosphatase BAS-like (PTP-BL) using a C-terminal combinatorial peptide phage library. Binding of PDZ3 to C-termini is preferentially governed by two cysteine residues at the P,1 and P,4 position and a valine residue at the P0 position. Interestingly, we found that this binding is lost upon addition of the reducing agent dithiothrietol, indicating that the interaction is disulfide-bridge-dependent. Site-directed mutagenesis of the single cysteine residue in PDZ3 revealed that this bridge formation does not occur intermolecularly, between peptide and PDZ3 domain, but rather is intramolecular. These data point to a preference of PTP-BL PDZ3 for cyclic C-terminal targets, which may suggest a redox state-sensing role at the cell cortex. [source] A simple and highly successful C-terminal sequence analysis of proteins by mass spectrometryPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 8 2008Hiroki Kuyama Dr. Abstract A simple and efficient method for C-terminal sequencing of proteins has long been pursued because it would provide substantial information for identifying the covalent structure, including post-translational modifications. However, there are still significant impediments to both direct sequencing from C termini of proteins and specific isolation of C-terminal peptides from proteins. We describe here a highly successful, de novo C-terminal sequencing method of proteins by employing succinimidyloxycarbonylmethyl tris (2,4,6-trimethoxyphenyl) phosphonium bromide and mass spectrometry. [source] Modulation of Ca2+ signalling in rat atrial myocytes: possible role of the ,1c carboxyl terminalTHE JOURNAL OF PHYSIOLOGY, Issue 2 2003Sun-Hee Woo Ca2+ influx through L-type Cav1.2 (,1c) Ca2+ channels is a critical step in the activation of cardiac ryanodine receptors (RyRs) and release of Ca2+ via Ca2+ -induced Ca2+ release(CICR). The released Ca2+, in turn, is the dominant determinant of inactivation of the Ca2+ current (ICa) and termination of release. Although Ca2+ cross-signalling is mediated by high Ca2+ fluxes in the microdomains of ,1c -RyR complexes, ICa -gated Ca2+ cross-signalling is surprisingly resistant to intracellular Ca2+ buffering and has steeply voltage-dependent gain, inconsistent with a strict CICR mechanism, suggesting the existence of additional regulatory step(s). To explore the possible regulatory role of the carboxyl (C)-terminal tail of ,1c in modulating Ca2+ signalling, we tested the effects of introducing two ,1c C-terminal peptides, LA (1571,1599) and K (1617,1636) on the central ,1c -unassociated Ca2+ -release sites of atrial myocytes, using rapid (240 Hz) two-dimensional confocal Ca2+ imaging. The frequency of spontaneously activating central sparks increased by approximately fourfold on dialysing LA- but not K-peptide into myocytes voltage-clamped at -80 mV. The rate but not the magnitude of caffeine (10 mM)-triggered central Ca2+ release was significantly accelerated by LA- but not K-peptide. Individual Ca2+ spark size and flux were larger in LA- but not in K-peptide-dialysed myocytes. Although LA-peptide did not change the amplitude or inactivation kinetics of ICa, LA-peptide did strongly enhance the central Ca2+ transients triggered by ICa at -30 mV (small ICa) but not at +20 mV (large ICa). In contrast, K-peptide had no effect on either ICa or the local Ca2+ transients. LA-peptide with a deleted calmodulin-binding region (LM1-peptide) had no significant effects on the central spark frequency but suppressed spontaneous spark frequency in the periphery. Our results indicate that the calmodulin-binding LA motif of the ,1c C-terminal tail may sensitize the RyRs, thereby increasing their open probability and providing for both the voltage-dependence of CICR and the higher frequency of spark occurrence in the periphery of atrial myocytes where the native ,1c -RyR complexes are intact. [source] Cellular autoreactivity against heat shock protein 60 in renal transplant patients: peripheral and graft-infiltrating responsesCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2006C. Caldas Summary Autoreactivity to heat shock protein 60 (Hsp60) has been implicated in the pathogenesis and regulation of chronic inflammation, especially in autoimmune diseases. In transplantation, there is a lack of information regarding the cytokine profile and specificity of cells that recognize self-Hsp60 as well as the kinetics of autoreactivity following transplantation. We studied the cellular reactivity of peripheral and graft-infiltrating lymphocytes against Hsp60 in renal transplant patients. Cytokine production induced by this protein in peripheral blood mononuclear cells indicated a predominance of interleukin (IL)-10 during the late post-transplantation period, mainly in response to intermediate and C-terminal peptides. Patients with chronic rejection presented reactivity to Hsp60 with a higher IL-10/interferon (IFN)-, ratio compared to long-term clinically stable patients. Graft-infiltrating T cell lines, cocultured with antigen-presenting cells, preferentially produced IL-10 after Hsp60 stimulation. These results suggest that, besides its proinflammatory activity, autoreactivity to Hsp60 in transplantation may also have a regulatory role. [source] | ||||||||||||||||