Effects of GP2 expression on secretion and endocytosis in pancreatic AR4-2J cells.
GP2 is the major membrane protein present in secretory granules of the exocrine pancreas. GP2's function is unknown, but a role in digestive enzyme packaging or secretion from secretory granules has been proposed. In addition, GP2 has been proposed to influence endocytosis and membrane recycling following stimulated secretion. Adenovirus-mediated GP2 overexpression in the rat pancreatic cell line AR4-2J was used to study its impact on digestive enzyme secretion and membrane recycling. Immunoelectron microscopy showed that GP2 and amylase co-localized in secretory granules in infected AR4-2J cells. CCK-8 stimulation resulted in a fourfold increase in amylase secretion with or without GP2 expression. GP2 expression also did not influence endocytosis following CCK-8 stimulation. Thus, GP2 expression in AR4-2J cells does not affect amylase packaging in secretory granules or stimulated secretion. GP2 expression also does not influence membrane recycling in response to stimulated stimulation in AR4-2J cells.
Department of Medicine and the Digestive Disease Center, Stanford University, Stanford, CA, USA.
Su
S
Yu
Ying
Y
Hao
Anson W
AW
Lowe
D000681:Amylases / Q000378:metabolism; D000818:Animals; D018267:Carcinoma, Acinar Cell / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D004705:Endocytosis; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D022161:Transport Vesicles / Q000378:metabolism / Q000648:ultrastructure
D058851:GPI-Linked Proteins; C066161:Gp2 protein, rat; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D000681:Amylases