Figure 12.

Newly synthesized galectin-4 resides intracellularly. Mg²⁺-precipitated (Mg²⁺) and microvillar (Mic) fractions were prepared from mucosal explants labeled for 1 h, extracted with CHAPS at 37°C for 10 min, and centrifuged through a sucrose gradient as described in MATERIALS AND METHODS. After centrifugation, the five bottom fractions of each gradient were pooled, acetone-precipitated, and analyzed by SDS-PAGE with the culture medium (Med). After electrophoresis and electrotransfer onto Immobilon, galectin-4 was visualized by autoradiography (A) and by Western blotting (B). Molecular mass values are indicated. (Notice that only the upper band of the 36-kDa doublet is radiolabeled, indicating that the lower band is generated by proteolysis after biosynthesis).