Fig. 4.

Involvement of Orai1 and STIM1 in focal adhesion turnover. Immunostaining of F-actin (red) and pFAK (green, A) or paxillin (green, B) of UhPK cells (kept in 0.07 mM Ca²⁺). UhPK cells were transfected with siOrai1, siSTIM1, siFAK, and siCtrl for 24 h before fixation. Small white boxes correspond to the magnified area of the image where pFAK (A) or paxillin (B) are shown in gray scale. (Scale bars: 10 µm.) (C) Calpain activity in UhPK cells treated with 60 nM siRNA against siOrai1 and siSTIM1 for 24 h. Cell lysates were obtained and assayed according to the fluorometric calpain activity kit (Merck Chemicals Ltd.) and compared with a provided positive control (Calpain).