A pool of intracellular phosphorylated asialoglycoprotein receptors which is not involved in endocytosis

Willem Stoorvogel, Alan L. Schwartz, Ger J. Strous, Robert Fallon

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

One proposed function of the asialoglycoprotein receptor in hepatocytes is to mediate the endocytosis of galactose and N-acetylgalactosamine-exposing glycoproteins. Recently we defined a pool of intracellular H1 subunits of the asialoglycoprotein receptor (ASGPR) in the human hepatoma cell line HepG2 which appeared not to be involved in endocytosis (Stoorvogel, W., Geuze, H. J., Griffith, J. M., Schwartz, A. L., and Strous, G. J. (1989) J. Cell Biol. 108, 2137-2148). In addition, a pool of stably phosphorylated intracellular ASGPR has been detected (Fallon, R. J., and Schwartz, A. L. (1988) J. Biol. Chem. 263, 13159-13166). In the current study we integrate these findings and provide evidence for the existence of two types of intracellular nonexchangeable compartments containing ASGPR. A transiently phosphorylated pool of ASGPR shuttles between the plasma membrane and endosomes, via a pathway identical to that of the transferrin receptor. The second pool comprises 20% of the total intracellular ASGPR, is stably phosphorylated at a serine residue, and is located in intracellular compartments devoid of recycling transferrin receptor. We refer to this ASGPR pool as the "silent pool." We furthermore show that the two receptor pools are confined to compartments exhibiting different buoyant densities on sucrose density gradients. ASGPR in the "silent pool" is fully glycosylated, suggesting a post-Golgi sorting mechanism for trafficking to this compartment. Possible functions of the "silent" ASGPR pool are discussed.

Original languageEnglish (US)
Pages (from-to)5438-5444
Number of pages7
JournalJournal of Biological Chemistry
Volume266
Issue number9
StatePublished - 1991
Externally publishedYes

Fingerprint

Asialoglycoprotein Receptor
Endocytosis
Transferrin Receptors
Acetylgalactosamine
Endosomes
Cell membranes
Galactose
Sorting
Serine
Sucrose
Recycling
Hepatocytes
Hepatocellular Carcinoma
Glycoproteins
Cells
Cell Membrane

ASJC Scopus subject areas

  • Biochemistry

Cite this

Stoorvogel, W., Schwartz, A. L., Strous, G. J., & Fallon, R. (1991). A pool of intracellular phosphorylated asialoglycoprotein receptors which is not involved in endocytosis. Journal of Biological Chemistry, 266(9), 5438-5444.

A pool of intracellular phosphorylated asialoglycoprotein receptors which is not involved in endocytosis. / Stoorvogel, Willem; Schwartz, Alan L.; Strous, Ger J.; Fallon, Robert.

In: Journal of Biological Chemistry, Vol. 266, No. 9, 1991, p. 5438-5444.

Research output: Contribution to journalArticle

Stoorvogel, W, Schwartz, AL, Strous, GJ & Fallon, R 1991, 'A pool of intracellular phosphorylated asialoglycoprotein receptors which is not involved in endocytosis', Journal of Biological Chemistry, vol. 266, no. 9, pp. 5438-5444.
Stoorvogel, Willem ; Schwartz, Alan L. ; Strous, Ger J. ; Fallon, Robert. / A pool of intracellular phosphorylated asialoglycoprotein receptors which is not involved in endocytosis. In: Journal of Biological Chemistry. 1991 ; Vol. 266, No. 9. pp. 5438-5444.
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