Cloning, sequence, and expression of a cDNA encoding hamster UDP-GlcNAc:dolichol phosphate N-acetylglucosamine-1-phosphate transferase

Xiaying Zhu, Mark A. Lehrman

Research output: Contribution to journalArticlepeer-review

80 Scopus citations

Abstract

UDP-GlcNAc:dolichol phosphate N-acetylglucosamine-1-phosphate transferase (GPT) catalyzes the initial reaction required for synthesis of dolichol-P-P-oligosaccharides. We report here on the sequence and expression of a full-length cDNA clone encoding hamster GPT. The cDNA predicts a protein of 408 amino acid residues including 10 hydrophobic segments. Several portions of the hamster GPT sequences constituting one-third of the protein have 60% or greater identity with yeast GTP, and one-half of the conserved sequence falls within the hydrophobic segments. In addition, hamster GPT has two copies of a putative dolichol recognition sequence recently identified in three yeast enzymes that interact with dolichol. The protein lacks KDEL or DEKKMP-type carboxyl-terminal ER sorting sequences. When expressed in COS-1 cells, the cDNA causes a 5-7-fold increase of GPT activity in membrane fractions. The activity was completely inhibitable by tunicamycin, and the primary product was shown to be GlcNAc-pyrophosphoryldolichol. This cDNA represents the first enzyme of the colichol-oligosaccharide biosynthetic pathway to be cloned from a vertebrate source and demonstrates structural homology between the enzymes of the yeast and mammalian pathways.

Original languageEnglish (US)
Pages (from-to)14250-14255
Number of pages6
JournalJournal of Biological Chemistry
Volume265
Issue number24
StatePublished - 1990

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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