The carp muscle-specific sub-isoenzymes of creatine kinase form distinct dimers at different temperatures

Proteomic profile and morphological characteristics of skeletal muscle from the fast- and slow-growing yellow perch (Perca flavescens)

The objective of the present study was to compare skeletal muscle proteomic profiles, histochemical characteristics, and expression levels of myogenic regulatory factors (MRFs) between fast- versus slow-growing yellow perch Perca flavescens and identify the proteins/peptides that might play a crucial role in the muscle growth dynamic. Yellow perch were nursed in ponds for 6 weeks from larval stage and cultured in two meter diameter tanks thereafter. The fingerlings were graded to select the top 10% and bottom 10% fish which represented fast- and slow-growing groups (31 yellow perch per each group). Our statistical analyses showed 18 proteins that had different staining intensities between fast- and slow-growing yellow perch. From those proteins 10 showed higher expression in slow-growers, and 8 demonstrated higher expression in fast-growers. Fast-growing yellow perch with a greater body weight was influenced by both the muscle fiber hypertrophy and mosaic hyperplasia compared to slow-growing fish. These hyperplastic and hypertrophic growth in fast-grower were associated with not only metabolic enzymes, including creatine kinase, glycogen phosphorylase, and aldolase, but also myoD and myogenin as MRFs. Overall, the results of the present study contribute to the identification of different expression patterns of gene products in fast- and slow-growing fish associated with their muscle growth.

Purification and stability of octameric mitochondrial creatine kinase isoform from herring (Clupea harengus) organ of vision

Creatine kinases (CKs) constitute a large family of isoenzymes that are involved in intracellular energy homeostasis. In cells with high and fluctuating energy requirements ATP level is maintained via phosphocreatine hydrolysis catalyzed by creatine kinase. In contrast to invertebrates and higher vertebrates, in poikilothermic vertebrates the adaptations for the regulation of energy metabolism by changes in the oligomeric state of CK isoforms are not well known. The present study aimed at identification of herring eye CK isoforms and focuses on factors affecting the CK-octamer stability. In addition to the CK octamer, three different dimeric isoforms of CK were detected by cellulose acetate native electrophoresis. Destabilization of octamer was studied in the presence of TSAC substrates and about 50% of octamers dissociated into dimers within 24h. Moreover, we found that the increase of temperature from 4 °C to 30 °C caused rapid inactivation of dimers in TSAC-treated samples but did not affect octameric structures. In a thermostability assay we demonstrated that octamers retain their activity even at 50 °C. Our results indicate that destabilization of the octameric structure can lead to loss of enzyme activity at higher temperatures (above 30 °C). Furthermore, our results based on N-terminal sequence analysis suggest that probably the mitochondrial s-type CK, rather than u-type, is predominantly expressed in herring eye. In conclusion the existence of four various CK isoforms in one organ may reflect complex regulation of energy metabolism in the phototransduction process in teleost fishes.

Analyzing cold tolerance mechanism in transgenic zebrafish (Danio rerio)

Low temperatures may cause severe growth inhibition and mortality in fish. In order to understand the mechanism of cold tolerance, a transgenic zebrafish Tg (smyd1:m3ck) model was established to study the effect of energy homeostasis during cold stress. The muscle-specific promoter Smyd1 was used to express the carp muscle form III of creatine kinase (M3-CK), which maintained enzymatic activity at a relatively low temperature, in zebrafish skeletal muscle. In situ hybridization showed that M3-CK was expressed strongly in the skeletal muscle. When exposed to 13 °C, Tg (smyd1:m3ck) fish maintained their swimming behavior, while the wild-type could not. Energy measurements showed that the concentration of ATP increased in Tg (smyd1:m3ck) versus wild-type fish at 28 °C. After 2 h at 13 °C, ATP concentrations were 2.16-fold higher in Tg (smyd1:m3ck) than in wild-type (P<0.05). At 13 °C, the ATP concentration in Tg (smyd1:m3ck) fish and wild-type fish was 63.3% and 20.0%, respectively, of that in wild-type fish at 28 °C. Microarray analysis revealed differential expression of 1249 transcripts in Tg (smyd1:m3ck) versus wild-type fish under cold stress. Biological processes that were significantly overrepresented in this group included circadian rhythm, energy metabolism, lipid transport, and metabolism. These results are clues to understanding the mechanisms underlying temperature acclimation in fish.

Identification of parvalbumin and two new thermolabile major allergens of Thunnus tonggol using a proteomics approach

BACKGROUND

The longtail tuna (Thunnus tonggol) is widely consumed in Asia. Parvalbumin, the main major allergen of fish, has been well identified in multiple fish species, yet little is known about the allergenic proteins in T. tonggol. Thus, the aim of this study was to characterize the major allergens of T. tonggol using a proteomics approach.

METHODS

Raw and boiled extracts of the fish were prepared. Fish proteins were separated by means of SDS-PAGE and two-dimensional (2-DE) electrophoresis. 1-DE immunoblotting of raw extract was performed with sera from fish-allergic patients. Ten sera were further analysed by 2-DE immunoblotting. Selected major allergenic protein spots were excised, trypsin digested and analysed by means of mass spectrometry.

RESULTS

SDS-PAGE of raw extract revealed 26 protein fractions, while boiled extract demonstrated fewer bands. The 2-DE gel profile of the raw extract further fractionated the protein bands to more than 100 distinct protein spots. 1-DE immunoblotting of raw extract exhibited two thermolabile protein fractions of 42 and 51 kDa as the major allergens, while the boiled extract only revealed a single IgE-binding band at 151 kDa. 2-DE immunoblotting of raw extract further detected numerous major IgE-reactive spots of 11-13, 42 and 51 kDa. Mass spectrometry analysis of the peptides generated from the 12, 42 and 51 kDa digested spots indicated that these spots were parvalbumin, creatine kinase and enolase, respectively.

CONCLUSIONS

In addition to parvalbumin, two new thermolabile allergens were identified as major allergenic proteins of T. tonggol. This study proved that both thermostable and thermolabile proteins are important in local tuna allergy and should be included in diagnostic strategies.

Zebrafish HSC70 promoter to express carp muscle-specific creatine kinase for acclimation under cold condition

Zebrafish (Danio rerio) is used as a model system for in vivo studies. To expand the research scope of physical, biochemical and physiological studies, a cold-tolerant model of zebrafish was developed. The common carp (Cyprinus carpio) muscle form of creatine kinase (CK, EC 2.7.3.2) can maintain enzymatic activity at a temperature of around 15°C. However, a cold-inducible promoter of zebrafish, hsc 70 (heat shock protein 70 cognate), is able to increase the expression of gene product by 9.8 fold at a temperature of 16°C. Therefore, the carp CK gene was promoted by hsc 70 and transfected into zebrafish embryos. Resulting transgenic zebrafish survived and could maintain its swimming behavior at 13°C, which was not possible with the wild-type zebrafish. The swimming distance of the transgenic fish was 42% greater than that of the wild type at 13°C. This new transgenic fish model is ideal for studies of ectothermal vertebrates in low-temperature environments.

Dissecting the key residues crucial for the species-specific thermostability of muscle-type creatine kinase

Species-specific protein thermal stability is closely correlated to the living conditions of the organism, especially to its body temperature. In this research, human and zebrafish muscle-type creatine kinases (MMCKs) were taken as model proteins to investigate the molecular adaptation of proteins in poikilothermal and homoiothermal animals. Both the optimal temperature for catalysis and the thermal stability of human MMCK was much higher than those of zebrafish MMCK. Sequence alignment identified 9 amino acid variations conserved in either the teleost MMCKs or the mammal and electric ray MMCKs. Bidirectional mutations were performed to find the residues with beneficial mutations. The results showed that two residues close to the dimer interface of MMCK, the 46th and 146th residue, were crucial for species-specific thermal stability.

[Cloning and tissue expression analysis of creatine kinase (M-CK) cDNA from the mandarin fish, Siniperca chuatsi]

The creatine kinase (CK) cDNA from the mandarin fish Siniperca chuatsi was cloned by RT-PCR and rapid amplification of cDNA ends (RACE) methods. The structural characteristics and phylogeny of this gene were analyzed. Sequence analysis revealed a 1586 bp cDNA sequence containing 92 bp 5'-untranslated region, 348 bp 3'-untranslated region and 1146 bp open reading frame (ORF), which encoded 381 amino acids. Conserved sequence blocks of vertebrate CKs and diagnostic boxes for the muscle CK (M-CK) isozyme were identified in S. chuatsi CK. Siniperca chuatsi CK showed a higher similarity with vertebrates M-CK isozyme than other CK isozymes (Brain CK, Mitochondrial CKs) and grouped with M-CK isozyme in CK phylogeny, which strongly supported that S. chuatsi CK belongs to M-CK isozyme type. Semi-quantitative RT-PCR analysis demonstrated that the M-CK transcript expression varied among the different tissues and was detected at a high level in skin, ovary, kidney, stomach, muscle and heart, but lower in eye, brain and liver.

Global cooling: cold acclimation and the expression of soluble proteins in carp skeletal muscle

The common carp (Cyprinus carpio) has a well-developed capacity to modify muscle properties in response to changes in temperature. Understanding the mechanisms underpinning this phenotypic response at the protein level may provide fundamental insights into the molecular basis of adaptive processes in skeletal muscle. In this study, common carp were subjected to a cooling regimen and soluble extracts of muscle homogenates were separated by 1-D SDS-PAGE and 2-DE. Proteins were identified using MALDI-TOF-MS and de novo peptide sequencing using LC-MS/MS. The 2-D gel was populated with numerous protein spots that were fragments of all three muscle isoforms (M1, M2 and M3) of carp creatine kinase (CK). The accumulation of the CK fragments was enhanced when the carp were cooled to 10 degrees C. The protein changes observed in the skeletal muscle of carp subjected to cold acclimation were compared to changes described in a previous transcript analysis study. Genes encoding CK isoforms were downregulated and the genes encoding key proteins of the ubiquitin-proteasome pathway were upregulated. These findings are consistent with a specific cold-induced enhancement of proteolysis of CK.

Monoclonal antibody FsC-47 against carp sperm creatine kinase

The enzyme creatine kinase (CK) plays a key role in energy homeostasis of cells with high and fluctuating energy requirements. As for spermatozoa, the activity of phosphocreatine shuttle, which directs energy from the mitochondria to sites of ATP consumption, is dependent on individual species. High activities of CK are observed in spermatozoa of nonvertebrate, fish, and birds, contrary to the low-level CK activity in mammalian spermatozoa. A new monoclonal antibody (MAb) to carp sperm creatine kinase was prepared. This antibody is applicable to large-scale immunochemical techniques. In this study, it was applied to the study of carp sperm motility, and the evaluation of the influence of CK on the quality and fertilization ability of carp spermatozoa.

Isolation, characterization and nucleotide sequence of the muscle isoforms of creatine kinase from the Antarctic teleost Chaenocephalus aceratus

Creatine kinase (CK) was isolated from the white muscle of the Antarctic icefish Chaenocephalus aceratus, which is deficient in glycolytic capacity. C. aceratus white myotomal creatine kinase (MMCK) displayed an apparent K(m) at 0.5 degrees C of 0.06 mM for ADP and 17 mM for Phosphocreatine. These K(m) values are similar to those reported for other vertebrate MMCKs at their physiologically relevant body temperatures. C. aceratus MMCK exhibited optimal activity at pH of 7.6-7.7 at 0.5 degrees C, in contrast to rabbit MMCK which had optimum activity at pH 6.2 at 30 degrees C. The apparent V(max) of C. aceratus MMCK at 0.5 degrees C is 94+/-4 S.D. (n=9) micromol ATP/min/mg (i.e. U/mg), which is comparable to rabbit MMCK assayed at 20 degrees C and 8-fold greater than rabbit MMCK measured at 0.5 degrees C. DEAE chromatography of C. aceratus white muscle CK resolved two distinct activity peaks. Cloning and sequencing of C. aceratus CK cDNAs confirmed that two muscle-specific isoforms of CK were expressed that were distinct from the mitochondrial and brain isoforms. Icefish MMCK was sensitive to transient temperature elevation, and the DEAE-fractionated forms were highly unstable. These results indicate that C. aceratus MMCK displays significant activity at physiological temperature and intracellular pH of icefish muscle that could contribute to sustaining energy charge during burst-swimming.