Internalization and recycling to serotonin-containing granules of the 80K intégral membrane protein exposed on the surface of secreting rat basophilie leukaemia cells

• Published in: Journal of cell science Vol. 92; no. 4; pp. 701 - 712
• Main Authors: Bonifacino, Juan S., Yuan, Lydia, Sandoval, Ignacio V.
• Format: Journal Article
• Language: English
• Published: 01.04.1989
• ISSN: 0021-9533; 1477-9137
• DOI: 10.1242/jcs.92.4.701

ABSTRACT The 80K (80x103Mr) integra! membrane protein, first described in the secretory granules of rat basophilie leukaemia (RBL) cells, is also localized to lysosomes in these cells. The protein displays the same distribution in natural killer lymphocytes (RNK-7), wherein it codistributes with cytolysin in secretory granules. In contrast, the protein is absent from the endocrine and exocrine secretory granules of rat pancreatic acinar and pituitary cells, respectively, where it is confined to lysosomes. The protein colocalizes with lysosomal intégral membrane proteins in ail the cells studied, indicating that is largely restricted to secretory granules with lysosomal properties (LSG) and lysosomes. The protein expressed on the surface of secreting RBL cells is internalized by endocytosis via coated pits, and found in coated vesicles, endosomes, multivesicular bodies and Golgi System, before being recycled to LSG and partly delivered to lysosomes. The recycled protein is re-expressed on the surface of cells stimulated to secrete a second time.