Abstract Background Prolonged endurance exercise is known to cause elevation of cardiac troponin I (cTnI). Previous studies have reported the correlation of several factors with exercise-induced cTnI ...release. However, the investigation of the predictors for elevated cTnI and postrace kinetics of cTnI after ultramarathon running is lacking, especially in an Oriental population. Methods Twenty-six participants, including eight hepatitis B virus carrier (HBVc) runners, who finished a 100-km ultramarathon in Taiwan were enrolled. For each participant, blood samples were collected 1 week before the race, as well as immediately and 24 hours after the finish. Results The results showed that 19 runners (73.1%) had postrace elevated cTnI levels and eight (30.8%) had elevated cTnI values lasting more than 24 hours after the run. A multiple linear regression analysis demonstrated that the HBV status was a factor related to the high level of cTnI after 24 hours of running ( β = 0.03, p = 0.08). The recovery of plasma cTnI levels was delayed in ultramarathon runners with latent HBV infection. Among HBVc runners, multiple linear regression analyses showed age ( β = −0.01), previous running experience ( β = −0.06), training distance ( β = 0.37), and 4 hours of running distance ( β = −0.04) as significant predictors of higher postrace cTnI levels. Conclusion For most athletes, cTnI values significantly increased immediately following the race in the absence of adverse clinical sequelae, and HBVc runners had higher and prolonged cTnI levels. While several factors are identified for such HBV effects, the specific causes need further elucidation.
Summary
The chromosomes of the soil bacteria Streptomyces, unlike those of most other bacteria, are linear DNA molecules. Their telomeres contain long‐terminal inverted repeats and covalently bound ...terminal proteins (TPs). These bacteria also harbour linear plasmids that share the same structural features. In this study, we demonstrated that the TP was covalently bound to the 5′ ends as proposed previously. A linear plasmid with chromosomal telomeres was constructed and used to purify the TPs of the Strep‐tomyces coelicolor A3(2) chromosome. A 20 kDa protein and its 10 kDa degradation product were isolated and their sequences determined by mass spectrometry. The coding sequence (tpgC) was about 100 kb from the right end of the chromosome. Two tpg homologues were identified by sequencing the 50 kb linear plasmid SLP2 of Streptomyces lividans: tpgSLP2 at 6 kb from the left end and a putative tpg pseudogene at 8 kb from the right. The latter was in a terminal repeat shared by the right end of SLP2 and both ends of the S. lividans chromosome. The lack of the typical Streptomyces codon preference in this open reading frame suggests that it is a pseudogene. The close physical linkage between the tpg genes and their cognate telomeres would favour their co‐segregation and co‐evolution. All the Tpg polypeptides are similar in length (184–185 amino acids) and sequences, which include a putative helix domain that is homologous to part of the DNA‐binding ‘thumb’ domain of HIV reverse transcriptase, and a putative amphiphilic beta‐sheet that may be involved in the observed self‐aggregation of the TP and/or the proposed membrane binding.
MgcRacGAP, a Rho GAP essential to cytokinesis, works both as a Rho GTPase regulator and as a scaffolding protein. MgcRacGAP interacts with MKLP1 to form the centralspindlin complex and associates ...with the RhoGEF Ect2. The GAP activity of MgcRacGAP is regulated by Aurora B phosphorylation. We have isolated B56ε, a PP2A regulatory subunit, as a new MgcRacGAP partner. We report here that (i) MgcRacGAP is phosphorylated by Aurora B and Cdk1, (ii) PP2A dephosphorylates Aurora B and Cdk1 phosphorylated sites and (iii) inhibition of PP2A abrogates MgcRacGAP/Ect2 interaction. Therefore, PP2A may regulate cytokinesis by dephosphorylating MgcRacGAP and its interacting partners.
Structured summary:MINT-6166761:Aurora B (uniprotkb:Q96GD4) phosphorylates (MI:0217) MgcRacGAP (uniprotkb:Q9H0H5) by protein kinase assay (MI:0424)MINT-6166774:Cdk1 (uniprotkb:P06493) phosphorylates (MI:0217) MgcRacGAP (uniprotkb:Q9H0H5) by protein kinase assay (MI:0424)MINT-6166653:PP2A (uniprotkb:P67775) dephosphorylates (MI:0203) MgcRacGAP (uniprotkb:Q9H0H5) by phosphatase assay (MI:0434)MINT-6166710, MINT-6166727, MINT-6166735:MgcRacGAP (uniprotkb:Q9H0H5)physically interacts (MI:0218) with B56ε (uniprotkb:Q16537) by coimmunoprecipitation (MI:0019)MINT-6166691:B56ε (uniprotkb:Q16537) physically interacts (MI:0218) with MgcRacGAP (uniprotkb:Q9H0H5) by far western blotting (MI:0047)MINT-6166556:MgcRacGAP (uniprotkb:Q9H0H5) physically interacts (MI:0218) with B56ε (uniprotkb:Q16537) by two-hybrid (MI:0018)MINT-6166634:MgcRacGAP (uniprotkb:Q9H0H5) physically interacts (MI:0218) with Ect2 (uniprotkb:Q9H8V3) by coimmunoprecipitation (MI:0019)MINT-6166596:MKLP-1 (uniprotkb:Q02241) physically interacts (MI:0218) with B56ε (uniprotkb:Q16537) , MgcRacGAP (uniprotkb:Q9H0H5), PP2A (uniprotkb:P67775) bycoimmunoprecipitation (MI:0019)
Post-translational modifications serve as important regulatory elements in modulating the transcriptional activity of the tumor suppressor protein p53. We have previously reported a tandem mass ...spectrometry-based method (viz. selected ion tracing analysis) that can be applied to the identification of phosphopeptides as well as exact mapping of the phosphorylated residues within. In this study, we describe the application of the same strategy for the identification of p300 acetyltransferase-mediated acetylation sites on p53. Consistent with the previous finding, lysines 370, 372, 373, 381, and 382 were detected by this modified selected ion tracing method as the target sites of p300 in vitro. Moreover, two novel acetylation sites, Lys-292 and Lys-305, were also found. Immunoblotting using anti-acetyl-Lys-305 antibody confirmed this discovery and demonstrated that Lys-305 could be acetylated by p300 both in vitro and in vivo. We also show that an alanine or glutamine substitution at Lys-305 (K305A or K305Q) suppressed the transcriptional activity of p53, whereas an arginine mutation (K305R) increased the transcriptional activity. Thus, p300 may further regulate the transcriptional activity of p53 through a novel acetylation site, Lys-305.
Notch signaling has been implicated to play a critical role in the tumorigenesis of neuroblastoma (NB) and can modulate calreticulin (CRT) expression that strongly correlates with tumor ...differentiation and favorable prognosis of NB. We thus sought to determine how Notch regulates CRT expression and affects NB tumor behavior.
The Notch-dependent regulation of CRT expression in cultured NB cells was analyzed by confocal microscopy and Western blotting. Notch1 protein expression in 85 NB tumors was examined by immunohistochemistry and correlated with the clinicopathologic/biological characters of NB patients. The progression of NB tumors in response to attenuated Notch signaling was examined by using a xenograft mouse model.
We showed that CRT is essential for the neuronal differentiation of NB cells elicited by inhibition of Notch signaling. This effect was mediated by a c-Jun-NH(2)-kinase-dependent pathway. Furthermore, NB tumors with elevated Notch1 protein expression were strongly correlated with advanced tumor stages, MYCN amplification, an undifferentiated histology, as well as a low CRT expression level. Most importantly, the opposing effect between Notch1 and CRT could reciprocally affect the survival of NB patients. The administration of a gamma-secretase inhibitor into a xenograft mouse model of NB significantly suppressed the tumor progression.
Our findings provide the first evidence that a c-Jun-NH(2)-kinase-CRT-dependent pathway is essential for the neuronal differentiation elicited by Notch signaling blockade and that Notch1 and CRT can synergistically predict the clinical outcomes of NB patients. The present data suggest that Notch signaling could be a therapeutic target for NB.
As the leading cause of cancer death worldwide, lung cancer lacks effective diagnosis tools and treatments to prevent its metastasis. Fortunately, secretome has clinical usages as biomarkers and ...protein drugs. To discover the secretome that influences lung adenocarcinoma metastasis, the hollow fiber culture (HFC) system was used along with label-free proteomics approach to analyze cell secretomes between CL1-0 and CL1-5 cell lines, which exhibit low and high metastatic potentials. Among the 703 proteins quantified, 50 possessed different levels between CL1-0 and CL1-5. PARK7 was a primary focus because of the lack of research involving lung adenocarcinoma. The cell proliferation, migration, and invasion properties of CL1-0, CL1-5, and A549 cells were significantly diminished when the expression of their PARK7 proteins was reduced. Conversely, these functions were promoted when PARK7 was overexpressed in CL1-0. In clinical expression, PARK7 levels within tissue specimens and plasma samples were significantly higher in the cancer group. This represents the first time the HFC system has been used with label-free quantification to discern the elements of metastasis in lung adenocarcinoma cell secretomes. Likewise, PARK7 has never been researched for its role in promoting lung adenocarcinoma progression.
Squamous cell carcinoma (SCC) accounts for more than 90% of malignant tumors of the oral cavity. In Taiwan, oral squamous cell carcinoma (OSCC) is among the most frequent malignancies, largely due to ...betal quid chewing. Despite the recent improvement in treatment results, the long-term outcome of OSCC generally remains poor, especially for those with advanced diseases. It is therefore desirable to identify potential biomarkers that may aid in risk stratification and perhaps the development of therapeutic targets. In this study, we exploited two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry to compare the proteome maps of 10 OSCC specimens with their adjacent nontumorous epithelia to identify differentially expressed proteins. Comparative proteomics indicated that 17 proteins were differentially expressed in OSCC with 11 up-regulated and 6 down-regulated proteins. These deregulated proteins participated in cytoskeletal functions, cell signaling, antiapoptosis, angiogenesis, lipid metabolism, drug metabolism, and protein translation/turnover. They were all associated with tumor development in various cancers. Among the dys-regulated proteins, the immunoexpression of three proteins including nicotinamide N-methyltransferase, apolipoprotein AI, and 14-3-3 zeta were evaluated in 38 OSCCs of testing cohort to confirm the proteomics data. Subsequently, the expression of 14-3-3 zeta, as the most relevant to OSCC progression determined by testing cohort, was further assessed in 80 OSCCs of independent validation cohort to identify the clinical relevance of its expression. By this comprehensive study, we identified 14-3-3 zeta as the only prognosticator of local recurrence-free survival (LRFS) and also an independently predicted factor of disease-specific survival (DSS).
Purpose: Neuroblastoma (NB) is a heterogeneous neoplasm. Detailed biological discrimination is critical for the effective treatment
of this disease. Because the tumor behavior of NB is closely ...associated with the histologic state of differentiation, we thus
aimed to identify novel differentiation-associated markers of NB with prognostic implication.
Experimental Design: A human NB cell line SH-SY5Y was used as a model system to explore potential biomarkers for the differentiation of NB by
proteomic analyses. Seventy-two NB tumor tissues were subsequently investigated by immunohistochemistry to validate the correlations
between the expression of a novel prognostic marker, various clinicopathologic and biological factors, and patient survival.
Results: Using two-dimensional differential gel electrophoresis, we found a total of 24 spots of proteins in SH-SY5Y cells whose expression
was enhanced following differentiation. Glucose-regulated protein 75 (GRP75) was unambiguously identified as one of the five
proteins that were dramatically up-regulated following differentiation. Immunohistochemical analyses of 72 NB tumor tissues
further revealed that positive GRP75 immunostaining is strongly correlated with differentiated histologies ( P < 0.001), mass-screened tumors ( P = 0.016), and early clinical stages ( P < 0.001) but inversely correlated with MYCN amplification ( P = 0.010). Univariate and multivariate survival analyses showed that GRP75 expression is an independent favorable prognostic
factor.
Conclusions: The present findings clearly showed that our proteomics-based novel experimental paradigm could be a powerful tool to uncover
novel biomarkers associated with the differentiation of NB. Our data also substantiate an essential role of GRP75 in the differentiation
of NB.
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