title: Interaction of nebulin SH3 domain with titin PEVK and myopalladin: implications for the signaling and assembly role of titin and nebulin.
abstract: Skeletal muscle nebulin is thought to determine thin filament length and regulate actomyosin interaction in a calcium/calmodulin or S100 sensitive manner. We have investigated the binding of nebulin SH3 with proline-rich peptides derived from the 28-mer PEVK modules of titin and the Z-line protein myopalladin, using fluorescence, circular dichroism and nuclear magnetic resonance techniques. Of the six peptides studied, PR2 of titin (VPEKKAPVAPPK) and myopalladin MyoP2 (646VKEPPPVLAKPK657) bind to nebulin SH3 with micromolar affinity (approximately 31 and 3.4 microM, respectively), whereas the other four peptides bind weakly (>100 microM). Sequence analysis of titins reveals numerous SH3 binding motifs that are highly enriched in the PEVK segments of titin isoforms. Our findings suggest that titin PEVK and myopalladin may play signaling roles in targeting and orientating nebulin to the Z-line during sarcomere assembly.
authors.affiliation: Muscle Proteomics and Nanotechnology Section, Laboratory of Muscle Biology, B50/Rm 1140, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Kan
authors.initials: K
authors.lastname: Ma
authors.forename: Kuan
authors.initials: K
authors.lastname: Wang
mesh_terms: D020816:Amino Acid Motifs; D001665:Binding Sites; D002942:Circular Dichroism; D064211:Connectin; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D009124:Muscle Proteins / Q000737:chemistry* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D020033:Protein Isoforms; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012518:Sarcomeres / Q000378:metabolism*; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence
chemical_list: D064211:Connectin; C426225:MYPN protein, human; D009124:Muscle Proteins; D010455:Peptides; D020033:Protein Isoforms; C577285:TTN protein, human; C035620:nebulin; D011494:Protein Kinases