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This Article Full Text Full Text (PDF) All Versions of this Article: 295/2/H647    most recent 00357.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Yuan, C. Articles by Solaro, R. J. PubMed PubMed Citation Articles by Yuan, C. Articles by Solaro, R. J.

Quantitative comparison of sarcomeric phosphoproteomes of neonatal and adult rat hearts

¹Department of Physiology and Biophysics, University of Illinois, Chicago, Illinois; ²School of Informatics, Indiana University, Bloomington, Indiana; and ³Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China

Submitted 4 April 2008 ; accepted in final form 9 June 2008

Neonatal hearts respond to stress and function in an environment quite different from adult hearts. There is evidence that these functional differences not only reflect modifications in the abundance and isoforms of sarcomeric proteins but also in the modulation of sarcomeric protein phosphorylation. Yet our understanding of changes in sarcomeric protein phosphorylation in development is incomplete. In the experiments reported here, we first quantified the intact sarcomeric protein phosphorylation status between neonatal and adult rat hearts by employing comparative two-dimensional (2-D) gel electrophoresis in conjunction with phosphoprotein-specific staining. Subsequently, we measured phosphorylation changes at the peptide level by employing high-resolution linear ion trap-Fourier transform (LTQ-FT) mass spectrometry analysis of titanium dioxide-enriched phosphopeptides differentially labeled with ¹⁶O/¹⁸O during in-gel digestion. We also employed Western blot analysis using phosphorylation site-specific antibodies to measure phosphorylation changes. Our data demonstrated the novel finding that phosphorylation levels of myosin-binding protein C (MyBP-C) at Ser²⁹⁵ and Ser³¹⁵ as well as tropomyosin at Ser²⁸³ increased, whereas phosphorylation levels of MyBP-C at Ser³²⁰ and myosin light chain 2 at Ser¹⁵ decreased in neonatal hearts compared with the same sites in adult hearts. Although our data highlight the significant challenges in understanding relations between protein phosphorylation and cardiac function, they do support the hypothesis that developmental changes in the modulation of protein are functionally significant and correlate with the prevailing physiological state.

neonatal; phosphorylation; ¹⁸O labeling; titanium dioxide; quantitative mass spectrometry; two-dimensional gel; tropomyosin; myosin light chain 2; myosin-binding protein C