Talin distribution during the differentiation of satellite cells isolated from rat skeletal muscle

Satellite cells (myogenic stem cells) dissociated from adult muscle tissue proliferate, fuse and form multinucleate myotubes when placed in culture. This study focused on the role of talin distribution during the differentiation of satellite cells. Talin plays a key role in anchoring actin filaments to integrins as well as to the plasma membrane in focal contacts. We demonstrated that there is a colocalization of talin and phosphoserine residues during the differentiation of satellite cells, and that it changes after TPA (a protein kinase C activator) treatment, and showed that talin existing in the cell-extracellular matrix and cell-cell contact area was not phosphorylated. In the presence of TPA (24 and 48 h exposure) the level of colocalization of both talin and phosphoserine residues was the same in the treated cells and in the control cells, but the level of talin phosphorylation was higher in the treated cells. We found that in myotubes from TPA treated cultures (144 h exposure to TPA), talin had localized near the cell membrane in the absence of phosphoserine residues, and that the level of talin phosphorylation was lower than in the control cells. We also demonstrated that the expression of talin during satellite cell differentiation was constant in both the control and TPA-treated cells.