moreover , since yolk platelets were able to fuse only with vesicles lacking occupied receptors ( in the case of albumin alone ) or with a compartment in which the specific ligand had been proteolytically cleaved and presumably released from its receptor ( in the case of vtg ) , we suggest that occupied receptors can act as a transmembrane signal which directs the postendocytotic compartmentation of proteins .
C0001924
albumin
C0033684
proteins