ecreted from the myoblasts to mediate the first steps of cell adhesion, and as the cells proliferated the deposited fibronectin and type IV collagen were organized into fibril networks. These data suggest that scaffolds for muscle repair may not be restricted to matrix proteins, and materials that trigger matrix protein secretion and adsorb these secreted proteins could be an alternative. We report here the use of a serum free culture system to examine myoblast proliferation and differentiation on solubilized and 3D muscle matrices and on a non-protein surface. We found that PLA2 treatment produced decellularised skeletal muscle retaining all the matrix proteins tested. The gene expression data and the alignment of MyHCB positive myotubes indicated that two-dimensional substrates of acellular muscle matrix may be superior to substrates of type I collagen, but comparable to fibronectin for supporting C2C12 differentiation. Furthermore, data from the 3D acellular muscle matrices indicate that particular “tracks” within natural muscle matrices favour myoblast attachment and alignment over other regions. This means the topography of the matrix directs the location of myotube formation and in vivo probably purchase PBTZ 169 facilitates the organization of myotubes into functioning muscle fibres in particular locations. In addition to the physical and chemical cues myoblasts receive from the surrounding matrix, they also rapidly secrete their own endogenous matrix proteins such as fibronectin, collagens I and IV and perlecan. That is, myoblasts interact with the existing matrix or surface, but also secrete their own matrix to create a localized microenvironment, which may PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19667254 contribute to myotube formation. Clearly, muscle ECM is more than the sum of its individual components and soluble muscle matrix substrates, or pure matrix proteins, are not substitutes for an intact 3D muscle matrix. ~~ Uncoordinated 51-like kinase 2 is a member of the serine/threonine kinase protein family, which plays an essential role in the regulation of autophagy in mammalian cells. Similar to ULK1, ULK2 is expressed ubiquitously, and its function appears to be redundant with that of ULK1, since ULK2 can compensate for the deletion of ULK1. Due to this phenomenon, the specific roles of ULK1 and ULK2 in autophagy are not yet clear. The central role of autophagy in normal cellular homeostasis and multiple diseases suggests that mechanistic insights into autophagy could drive the development of novel therapeutic approaches. Few enzymes exert as broad PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19666007 a regulatory influence on cellular function as does ULK2, which is involved in many fundamental biological processes, including cell fate determination, metabolism, transcriptional control, and oncogenesis. Similar to other ULK family members, ULK2 also plays a central role in the autophagy signaling pathway. Recently, others have suggested that the activity of ULK2 must be carefully regulated by mechanisms that are individually tailored to each substrate in order to avoid indiscriminate phosphorylation by ULK1. Although the mechanisms that regulate ULK2 in the autophagic process are not yet fully understood, precise control appears to be achieved through a combination of phosphorylation, localization, and interactions with ULK2 binding proteins. Unlike ULK1, which is predominantly found in the cytosol, 
ULK2 is located mainly in the nucleus, but can also be found in the cytosol and mitochondria. However, the mechanism by which ULK2 is localize