Cytoskeleton-associated PDZ-LIM protein, ALP, acts on serum response factor activity to regulate muscle differentiation

Journal ArticleIn this report, an antisense RNA strategy has allowed us to show that disruption of ALP expression affects the expression of the muscle transcription factors myogenin and MyoD, resulting in the inhibition of muscle differentiation. Introduction of a MyoD expression construct into ALP-antisense cells is sufficient to restore the capacity of the cells to differentiate, illustrating that ALP function occurs upstream of MyoD

CRP1, a LIM domain protein implicated in muscle differentiation, interacts with α-actinin

Journal ArticleMembers of the cysteine-rich protein (CRP) family are LIM domain proteins that have been implicated in muscle differentiation. One strategy for defining the mechanism by which CRPs potentiate myogenesis is to characterize the repertoire of CRP binding partners

Purification and characterization of an α-actinin-binding PDZ-LIM protein that is up-regulated during muscle differentiation

Journal Articleα-Actinin is required for the organization and function of the contractile machinery of muscle. In order to understand more precisely the molecular mechanisms by which α-actinin might contribute to the formation and maintenance of the contractile apparatus within muscle cells, we performed a screen to identify novel α-actinin binding partners present in chicken smooth muscle cells. In this paper, we report the identification, purification, and characterization of a 36-kDa smooth muscle protein (p36) that interacts with α-actinin

Circulating extracellular vesicle-carried PTP1B and PP2A phosphatases as regulators of insulin resistance

We thank SCAHU staff of Angers University for taking care of animals, the SCIAM platform, especially Florence Manero, for technical assistance for electron microscopy imaging, and the staff of University Hospital Centre of Angers analysis of clinical data of NUMEVOX cohort. Also, we thank the Department of Pathology of University Hospital Centre of Angers for help on histological analysis.Peer reviewe

M19 Modulates Skeletal Muscle Differentiation and Insulin Secretion in Pancreatic β-Cells through Modulation of Respiratory Chain Activity

Mitochondrial dysfunction due to nuclear or mitochondrial DNA alterations contributes to multiple diseases such as metabolic myopathies, neurodegenerative disorders, diabetes and cancer. Nevertheless, to date, only half of the estimated 1,500 mitochondrial proteins has been identified, and the function of most of these proteins remains to be determined. Here, we characterize the function of M19, a novel mitochondrial nucleoid protein, in muscle and pancreatic β-cells. We have identified a 13-long amino acid sequence located at the N-terminus of M19 that targets the protein to mitochondria. Furthermore, using RNA interference and over-expression strategies, we demonstrate that M19 modulates mitochondrial oxygen consumption and ATP production, and could therefore regulate the respiratory chain activity. In an effort to determine whether M19 could play a role in the regulation of various cell activities, we show that this nucleoid protein, probably through its modulation of mitochondrial ATP production, acts on late muscle differentiation in myogenic C2C12 cells, and plays a permissive role on insulin secretion under basal glucose conditions in INS-1 pancreatic β-cells. Our results are therefore establishing a functional link between a mitochondrial nucleoid protein and the modulation of respiratory chain activities leading to the regulation of major cellular processes such as myogenesis and insulin secretion

Nuclear translocation of the cytoskeleton-associated protein, smALP, upon induction of skeletal muscle differentiation.

International audienceThe skALP isoform has been shown to play a critical role in actin organization and anchorage within the Z-discs of skeletal muscles, but no data is available on the function of the smALP isoform in skeletal muscle cells. Here, we show that upon induction of differentiation a nuclear translocation of smALP from the cytoplasm to the nucleus of C2C12 myoblasts, concomitant to an up-regulation of the protein expression, occurs in parallel with the nuclear accumulation of myogenin. Moreover, we demonstrate that the LIM domain of smALP is essential for the nuclear translocation of the protein

Fem1a is a mitochondrial protein up-regulated upon ischemia–reperfusion injury

AbstractVarious expression studies have shown a preferential muscle expression of the mouse Fem1a gene, but no data is available on the subcellular localization of the corresponding protein. Here, using a specific antibody, we show that Fem1a is expressed preferentially in cardiac muscle, brain and liver. Moreover, using immunofluorescence and electron microscopy, as well as biochemical assays, we demonstrate that Fem1a is localized within mitochondria of C2C12 myoblasts and cardiac muscle cells. Finally, we show that the expression of Fem1a, which is a cellular partner of the EP4 receptor for prostaglandin E2, is increased in mouse hearts after myocardial infarction