since there is high labeling of the secretory granules from 40 min to 4 hr and the labeled granules are associated with the golgi apparatus at early times , it is proposed that collagen precursors are processed through rer and golgi apparatus , packaged into secretory granules and then transported to the cell surface where type iv collagen or its precursors are released and subsequently deposited into reichert 's membrane .
C0009325
collagen
C0009333
type iv collagen