Circulation research · 2010
Myomasp/LRRC39, a heart- and muscle-specific protein, is a novel component of the sarcomeric M-band and is involved in stretch sensing.
СтатьяПоддержка исследования: вне правительства СШАНазвание и аннотация: Перевод в очереди
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Will Rainer D, Eden Matthias, Just Steffen, Hansen Arne, Eder Alexandra, Frank Derk, Kuhn Christian, Seeger Thalia S, Oehl Ulrike, Wiemann Stefan, Korn Bernhard, Koegl Manfred, Rottbauer Wolfgang, Eschenhagen Thomas, Katus Hugo A, Frey Norbert
Аннотация
RATIONALE AND OBJECTIVE: The M-band represents a transverse structure in the center of the sarcomeric A-band and provides an anchor for the myosin-containing thick filaments. In contrast to other sarcomeric structures, eg, the Z-disc, only few M-band-specific proteins have been identified to date, and its exact molecular composition remains unclear.
METHODS AND RESULTS: Using a bioinformatic approach to identify novel heart- and muscle-specific genes, we found a leucine rich protein, myomasp (Myosin-interacting, M-band-associated stress-responsive protein)/LRRC39. RT-PCR and Northern and Western blot analyses confirmed a cardiac-enriched expression pattern, and immunolocalization of myomasp revealed a strong and specific signal at the sarcomeric M-band. Yeast 2-hybrid screens, as well as coimmunoprecipitation experiments, identified the C terminus of myosin heavy chain (MYH)7 as an interaction partner for myomasp. Knockdown of myomasp in neonatal rat ventricular myocytes (NRVCMs) led to a significant upregulation of the stretch-sensitive genes GDF-15 and BNP. Conversely, the expression of MYH7 and the M-band proteins myomesin-1 and -2 was found to be markedly reduced. Mechanistically, knockdown of myomasp in NRVCM led to a dose-dependent suppression of serum response factor-dependent gene expression, consistent with earlier observations linking the M-band to serum response factor-mediated signaling. Finally, downregulation of myomasp/LRRC39 in spontaneously beating engineered heart tissue constructs resulted in significantly lower force generation and reduced fractional shortening. Likewise, knockdown of the myomasp/LRRC39 ortholog in zebrafish resulted in severely impaired heart function and cardiomyopathy in vivo.
CONCLUSIONS: These findings reveal myomasp as a previously unrecognized component of an M-band-associated signaling pathway that regulates cardiomyocyte gene expression in response to biomechanical stress.
METHODS AND RESULTS: Using a bioinformatic approach to identify novel heart- and muscle-specific genes, we found a leucine rich protein, myomasp (Myosin-interacting, M-band-associated stress-responsive protein)/LRRC39. RT-PCR and Northern and Western blot analyses confirmed a cardiac-enriched expression pattern, and immunolocalization of myomasp revealed a strong and specific signal at the sarcomeric M-band. Yeast 2-hybrid screens, as well as coimmunoprecipitation experiments, identified the C terminus of myosin heavy chain (MYH)7 as an interaction partner for myomasp. Knockdown of myomasp in neonatal rat ventricular myocytes (NRVCMs) led to a significant upregulation of the stretch-sensitive genes GDF-15 and BNP. Conversely, the expression of MYH7 and the M-band proteins myomesin-1 and -2 was found to be markedly reduced. Mechanistically, knockdown of myomasp in NRVCM led to a dose-dependent suppression of serum response factor-dependent gene expression, consistent with earlier observations linking the M-band to serum response factor-mediated signaling. Finally, downregulation of myomasp/LRRC39 in spontaneously beating engineered heart tissue constructs resulted in significantly lower force generation and reduced fractional shortening. Likewise, knockdown of the myomasp/LRRC39 ortholog in zebrafish resulted in severely impaired heart function and cardiomyopathy in vivo.
CONCLUSIONS: These findings reveal myomasp as a previously unrecognized component of an M-band-associated signaling pathway that regulates cardiomyocyte gene expression in response to biomechanical stress.
Предметные рубрики MeSH
Amino Acid SequenceAnimalsAnimals, NewbornBlotting, NorthernBlotting, WesternCardiac MyosinsCardiomyopathiesCarrier ProteinsCells, CulturedCloning, MolecularConnectinEmbryo, NonmammalianGene Expression ProfilingGene Expression RegulationGrowth Differentiation Factor 15HumansImmunohistochemistryImmunoprecipitationLeucine-Rich Repeat ProteinsMaleMechanotransduction, CellularMiceMice, Inbred C57BLMolecular Sequence DataMuscle ProteinsMuscle, SkeletalMyocardial ContractionMyocytes, CardiacMyosin Heavy ChainsNatriuretic Peptide, BrainOligonucleotide Array Sequence AnalysisProtein Interaction Domains and MotifsProtein Interaction MappingProteinsRNA InterferenceRatsRats, Sprague-DawleyRats, WistarReverse Transcriptase Polymerase Chain ReactionSarcomeresSerum Response FactorStress, MechanicalTransfectionTwo-Hybrid System TechniquesZebrafish