Human low density lipoprotein receptor expressed in Xenopus oocytes. Conserved signals for O-linked glycosylation and receptor-mediated endocytosis.

S. L. Peacock, M. P. Bates, D. W. Russell, M. S. Brown, J. L. Goldstein

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

The human low density lipoprotein (LDL) receptor is shown to carry out efficient receptor-mediated endocytosis in Xenopus laevis oocytes. Microinjection of mRNAs encoding the human receptor led to synthesis of a 120-kDa precursor possessing high mannose N-linked sugars and core O-linked sugars. During its transport to the cell surface, the protein increased in apparent size to 160 kDa, which is similar to the change that occurs in human cells. This increase was not seen when the receptor lacked the serine/threonine-rich region that undergoes O-linked glycosylation. The surface receptors bound 125I-LDL at 0 degrees C and internalized it with a half-time of 2 min when the cells were warmed to 19 degrees C. The rate of internalization was slowed by 7-fold when a single residue in the cytoplasmic domain (Tyr807) was changed to a cysteine, an alteration that slows incorporation into coated pits in mammalian cells. Deletion of the cytoplasmic domain abolished rapid internalization. We conclude that the signals for O-linked glycosylation and receptor-mediated endocytosis of the LDL receptor have been conserved throughout vertebrate evolution.

Original languageEnglish (US)
Pages (from-to)7838-7845
Number of pages8
JournalThe Journal of biological chemistry
Volume263
Issue number16
StatePublished - Jun 5 1988

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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