Arg/Abl‐binding protein, a Z‐body and Z‐band protein, binds sarcomeric, costameric, and signaling molecules

Abstract

ArgBP2 (Arg/Abl-Binding Protein) is expressed at high levels in the heart and is localized in the Z-bands of mature myofibrils. ArgBP2 is a member of a small family of proteins that also includes vinexin and CAP (c-Cbl-associated protein), all characterized by having one sorbin homology (SOHO) domain and three C-terminal SH3 domains. Antibodies directed against ArgBP2 also react with the Z-bodies of myofibril precursors: premyofibrils and nascent myofibrils. Expression in cardiomyocytes of plasmids encoding Yellow Fluorescent Protein (YFP) fused to either full length ArgBP2, the SOHO, mid-ArgBP or the SH3 domains of ArgBP2 led to Z-band targeting of the fusion proteins, whereas an N-terminal fragment lacking these domains did not target to Zbands. Although ArgBP2 is not found in skeletal muscle cells, YFP-ArgBP2 did target to Zbodies and Z-bands in cultured myotubes. GST-ArgBP2-SH3 bound actin, alpha-actinin and vinculin proteins in blot overlays, cosedimentation assays, and EM negative staining techniques. Over-expression of ArgBP2 and ArgBP2-SH3 domains, but not YFP alone, led to loss of myofibrils in cardiomyocytes. Fluorescence Recovery After Photobleaching was used to measure the rapid dynamics of both the full length and some truncated versions of ArgBP2. Our results indicate that ArgBP2 may play an important role in the assembly and maintenance of myofibrils in cardiomyocytes.

Jasplakinolide reduces actin and tropomyosin dynamics during myofibrillogenesis

“…By day four in culture, premyofibrils bounded by Z‐bodies spaced 1 micron or less apart are evident at the spreading ends and sides of the myotubes, as well as in the central regions of the myotube where a few mature myofibrils can be detected (Figs. a and b) [Rhee et al, ; Sanger et al, ; White et al, ]. One day later in culture premyofibrils continue to form in the elongating ends and along edges of the myotubes (Figs.…”

SORBS2transcription is activated by telomere position effect–over long distance upon telomere shortening in muscle cells from patients with facioscapulohumeral dystrophy

“…S10). SORBS2 protein has previously been reported to be present in cardiac but not skeletal muscle (Wang et al 1997;Sanger et al 2010). We used immunohistochemistry (IHC) for protein localization and RT-PCR for RNA expression to examine whether SORBS2 was expressed in skeletal muscle and whether its expression was modified in FSHD biopsies.…”

“…SORBS2 has previously been detected at the Z-line of cardiac muscle, and overexpression in cardiac cells causes sarcomere disruption (Sanger et al 2010). SORBS2 is also localized at the intercalated disk of cardiomyocytes (Sanger et al 2010) and has been shown to interact with multiple proteins (Roignot and Soubeyran 2009;Lamberti et al 2011;Murase et al 2012;Roignot et al 2014).…”

“…SORBS2 is also localized at the intercalated disk of cardiomyocytes (Sanger et al 2010) and has been shown to interact with multiple proteins (Roignot and Soubeyran 2009;Lamberti et al 2011;Murase et al 2012;Roignot et al 2014). As a member of the Sorbin family, SORBS2 interacts with actin and can mediate signal-transduction events, from cell adhesion (Murase et al 2012), migration Soubeyran 2009), proliferation (Haglund et al 2004), to cell homeostasis (Roignot et al 2014).…”

Comparative proteomics analysis ofmyocardium inmouse model of diabetic cardiomyopathy using the iTRAQ technique

“…31 It belongs to a small family of adaptor proteins having sorbin homology domains; Sorbs2 is highly expressed in cardiac muscle cells at sarcomeric Z-disc structures, as well as in other cells at actin stress fibers and the nucleus. 31,32 Sorbs2 is considered an adapter protein that plays a significant role in cytoskeletal organization, cell adhesion and signaling pathways. 33 A proteomic analysis of cardiac tissues from patients has suggested that Sorbs2 is released from injured cardiac tissue into the bloodstream upon lethal acute myocardial infarction (AMI).…”