Marini M.,University of Verona |
Guglielmi V.,University of Verona |
Faulkner G.,Muscle Molecular Biology Group |
Piffer S.,University of Verona |
And 2 more authors.
Myofibrillar myopathies (MFMs) are a group of inherited or sporadic neuromuscular disorders morphologically characterized by foci of myofibril dissolution, disintegration of the Z-disk, and insoluble protein aggregates within the muscle fibers. The diagnosis is based on muscle biopsy. Light and electron microscopy has a central role in the diagnostic work up, and immunohistochemistry shows abnormal deposition of several proteins including αB-crystallin, desmin, and myotilin. In contrast, immunoblotting does not have any diagnostic value because it does not highlight differences in the amount of involved proteins. We investigated the pattern and level expression of desmin, αB-crystallin, myotilin, and ZASP (Z-band alternatively spliced PDZ motif-containing protein) in muscle of seven patients with MFMs by immunoblotting after SDS-PAGE and 2D-PAGE using two different solubilizing solutions, one radioimmunoprecipitation assay (RIPA) buffer, and the other urea-containing buffer. Our data demonstrated that urea-containing buffer improves the solubilization and recovery of desmin, αB-crystallin, myotilin, and ZASP as compared with RIPA buffer and that the total content of these proteins is increased in muscles of patients. The present results provide evidence that immunoblotting is an additional tool for confirming diagnosis of MFMs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Belgrano A.,Muscle Molecular Biology Group |
Rakicevic L.,University of Belgrade |
Mittempergher L.,University of Padua |
Campanaro S.,University of Padua |
And 6 more authors.
Background: Ankrd2 (also known as Arpp) together with Ankrd1/CARP and DARP are members of the MARP mechanosensing proteins that form a complex with titin (N2A)/calpain 3 protease/myopalladin. In muscle, Ankrd2 is located in the I-band of the sarcomere and moves to the nucleus of adjacent myofibers on muscle injury. In myoblasts it is predominantly in the nucleus and on differentiation shifts from the nucleus to the cytoplasm. In agreement with its role as a sensor it interacts both with sarcomeric proteins and transcription factors. Methodology/Principal Findings: Expression profiling of endogenous Ankrd2 silenced in human myotubes was undertaken to elucidate its role as an intermediary in cell signaling pathways. Silencing Ankrd2 expression altered the expression of genes involved in both intercellular communication (cytokine-cytokine receptor interaction, endocytosis, focal adhesion, tight junction, gap junction and regulation of the actin cytoskeleton) and intracellular communication (calcium, insulin, MAPK, p53, TGF-β and Wnt signaling). The significance of Ankrd2 in cell signaling was strengthened by the fact that we were able to show for the first time that Nkx2.5 and p53 are upstream effectors of the Ankrd2 gene and that Ankrd1/CARP, another MARP member, can modulate the transcriptional ability of MyoD on the Ankrd2 promoter. Another novel finding was the interaction between Ankrd2 and proteins with PDZ and SH3 domains, further supporting its role in signaling. It is noteworthy that we demonstrated that transcription factors PAX6, LHX2, NFIL3 and MECP2, were able to bind both the Ankrd2 protein and its promoter indicating the presence of a regulatory feedback loop mechanism. Conclusions/Significance: In conclusion we demonstrate that Ankrd2 is a potent regulator in muscle cells affecting a multitude of pathways and processes. © 2011 Belgrano et al. Source