Constitutive upregulations of titin-based signalling proteins in KY deficient muscles.

An increase in the expression of stretch/stress response elements in fast and slow muscles has been previously described in a transcriptional profiling of KY deficient muscles. Here, we have characterized the induction of this titin-based family of signalling proteins in ky/ky muscles at the protein level. Changes in expression of MLP, MARP2 and Xin have been related to the onset of dystrophic and adaptive changes that operate in ky/ky muscles.

Filamin C interacts with the muscular dystrophy KY protein and is abnormally distributed in mouse KY deficient muscle fibres.

The KY protein has been implicated in a neuromuscular dystrophy in the mouse, but its role in muscle function remains unclear. Here, we show that KY interacts with several sarcomeric cytoskeletal proteins including, amongst others, filamin C and the slow isoform of the myosin-binding protein C. These interactions were confirmed in vitro and because of its central role in skeletal muscle disease, characterized in more detail for filamin C.