Involvement of membrane-bound transglutaminase in the invagination of transferrin into rat reticulocyte plasma membrane.

We demonstrated the invagination of transferrin into reticulocyte plasma membrane to learn whether membrane-bound transglutaminase (TGase, a Ca(2+)-dependent enzyme) is involved in this invagination. The invagination was assessed by acid-resistance assay and antibody-inaccessibility assay. The invagination was blocked in the absence of ATP.

Internalization model using rat liver plasma membrane for receptor-mediated endocytosis of epidermal growth factor.

We have demonstrated the internalization of epidermal growth factor (EGF) using membrane isolated from rat liver. The isolated membrane exhibited a saturation curve of the binding of 125I-EGF. Furthermore, competition between the binding of 125I-EGF and unlabeled EGF to the isolated membrane was observed.