Characterisation and expression of calpain family members in relation to nutritional status, diet composition and flesh texture in gilthead sea bream (Sparus aurata)

• Published in: PLoS ONE
• Main Authors: Salmeron, Cristina, Garcia de la Serrana Castillo, Daniel, Jimenez-Amilburu, Vanesa, Fontanillas, Ramon, Navarro, Isabel, Johnston, Ian A., Gutierrez, Joaquim, Capilla, Encarnacion
• Other Authors: University of St Andrews. School of Biology, University of St Andrews. Marine Alliance for Science & Technology Scotland, University of St Andrews. Scottish Oceans Institute, University of St Andrews. Centre for Research into Ecological & Environmental Modelling
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: Trout oncorhynchus-mykiss; Calcium-dependent protease; Bass dicentrarchus-labrax; Muscle-specific calpain; Skeletal-muscle; Atlantic salmon; Growth dynamics; Myofibril fragmentation; Longissimus muscle; Messenger-RNA; QH301 Biology; QH301
• Online Access: http://hdl.handle.net/10023/5012; https://doi.org/10.1371/journal.pone.0075349

EC is a Ramón y Cajal researcher fellow from the “Ministerio de Ciencia e Innovaci” (MICINN). This work was supported by funds from the MICINN (AGL2009-12427 and AGL2010-17324), the Catalonian Government (2009SGR-00402) and the “Xarxa de Referència d’R+D+I en Aqüicultura” and the European Union through the project LIFECYCLE (FP7-222719). Calpains are non-lysosomal calcium-activated neutral proteases involved in a wide range of cellular processes including muscle proteolysis linked to post-mortem flesh softening. The aims of this study were (a) to characterise several members of the calpain system in gilthead sea bream and (b) to examine their expression in relation to nutritional status and muscle tenderisation. We identified the complete open reading frame of gilthead sea bream calpains1-3, sacapn1, sacapn2, sacapn3, and two paralogs of the calpain small subunit1, sacapns1a and sacapns1b. Proteins showed 63-90% sequence identity compared with sequences from mammals and other teleost fishes, and the characteristic domain structure of vertebrate calpains. Transcripts of sacapn1, sacapn2, sacapns1a and sacapns1b had a wide tissue distribution, whereas sacapn3 was almost exclusively detected in skeletal muscle. Next, we assessed transcript expression in skeletal muscle following alteration of nutritional status by (a) fasting and re-feeding or (b) feeding four experimental diets with different carbohydrate-to-protein ratios. Fasting significantly reduced plasma glucose and increased free fatty acids and triglycerides, together with a significant increase in sacapns1b expression. Following 7 days of re-feeding, plasma parameters returned to fed values and sacapn1, sacapn2, sacapns1a and sacapns1b expression was significantly reduced. Furthermore, an increase in dietary carbohydrate content (11 to 39%) diminished growth but increased muscle texture, which showed a significant correlation with decreased sacapn1 and sacapns1a expression, whilst the other calpains remained unaffected. This study has demonstrated that ...