6533b7d1fe1ef96bd125d5ee

RESEARCH PRODUCT

Secretion of Protein-bound Hydroxyproline from Moss Callus Cells

subject

description

Abstract A glycoprotein rich in hydroxyproline was found in wall preparations of callus cells of the moss Physcomitrium pyriforme Brid. It is apparently attached to the non-cellulosic polysaccharides of the wall, and the majority is extractable by boiling the wall fraction or by using a chaotropic salt at room temperature. A pulse-chase technique was used to study the transport of this protein to the wall. Cytochalasin B seems to inhibit its secretion from the callus cells. Some of this wall-associated protein is probably secreted from the cells into the medium. Electron microscopic evidence shows vesicular activity in the cytoplasm and secretion and incorporation into the wall layers (not shown). The protein probably functions in the maintenance of cell shape in the moss callus tissue, being partly secreted out of the callus cells before the filamentous morphology appears.