Nucleoplasmic and cytoplasmic glycoproteins.

Gerald Warren Hart, R. S. Haltiwanger, G. D. Holt, W. G. Kelly

Research output: Contribution to journalArticlepeer-review

Abstract

We have described a new form of protein glycosylation in which N-acetylglucosamine is glycosidically linked to the hydroxyl of serine or threonine (O-GlcNAc). Unlike most other forms of protein glycosylation, O-GlcNAc is predominantly localized in the nuclear and cytoplasmic compartments of cells, where it occurs on important nuclear pore glycoproteins, well-characterized cytoskeletal proteins, as well as on many chromatin proteins, including factors that regulate gene transcription. Gas-phase protein sequencing of three O-GlcNAc-modified proteins has identified a common structural feature at sites of O-GlcNAc addition. An assay for UDP-GlcNAc:polypeptide O-GlcNAc transferase has been developed. The enzyme appears to be membrane-associated, its active site is cytoplasmic, and it has an absolute requirement for Mn2+. We are now purifying this glycosyltransferase, characterizing its substrate specificity, and determining the extent of elongation of attached saccharide moieties. The functions of O-GlcNAc remain largely unknown, but it may be important in blocking phosphorylation sites, it may be required for the assembly of specific multiprotein complexes, it might serve as a nuclear transport signal, or it may be directly involved in the active transport of macromolecules across nuclear pores.

Original languageEnglish (US)
Pages (from-to)102-112, discussion 112
JournalCiba Foundation symposium
Volume145
StatePublished - 1989

ASJC Scopus subject areas

  • Medicine(all)

Fingerprint Dive into the research topics of 'Nucleoplasmic and cytoplasmic glycoproteins.'. Together they form a unique fingerprint.

Cite this