Alternative O-glycosylation/O-phosphorylation of the murine estrogen receptor beta.
Estrogen receptor beta, a homologue to estrogen receptor alpha, is a new member of the steroid hormone receptor family. Recently, we documented that estrogen receptor alpha, like other transcription factors, is modified by O-linked N-acetylglucosamine (O-GlcNAc), a ubiquitous transitory posttranslational modification on nuclear and cytoplasmic proteins. Here, we report that estrogen receptor beta is alternatively modified by either O-GlcNAc or O-phosphate. Lectin chromatography of in vitro translated protein first suggested that murine estrogen receptor beta (mER-beta) is O-GlcNAcylated. Structural characterization of the carbohydrate moieties on mER-beta, overexpressed in insect Sf9 cells, confirmed the presence of O-GlcNAc. mER-beta, overexpressed in mammalian cells, is also O-GlcNAcylated. The major site of O-GlcNAc on mER-beta from Sf9 cells is Ser(16) near the N-terminus. Concomitant analyses also documented the O-phosphorylation of mER-beta at Ser(16). MALDI-TOF mass spectrometry showed alternative occupancy of this locus by these two abundant and dynamic posttranslational modifications. The localization of a major O-GlcNAc/O-phosphate site in proximity of the transactivation domain and as part of a PEST region (target sequences for rapid protein degradation) on mER-beta suggests that these modifications may play a role in regulating estrogen receptor beta transactivation and turnover.
Cheng
X
X
Department of Biological Chemistry, School of Medicine, The Johns Hopkins University, 725 North Wolfe Street, Baltimore, Maryland 21205-2185, USA.
Cole
R N
RN
Zaia
J
J
Hart
G W
GW
D000117:Acetylglucosamine / Q000302:isolation & purification / Q000378:metabolism; D000215:Acylation; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002236:Carbohydrate Conformation; D047629:Estrogen Receptor beta; D006031:Glycosylation; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D017434:Protein Structure, Tertiary / Q000235:genetics; D011960:Receptors, Estrogen / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera / Q000235:genetics; D015533:Transcriptional Activation
D047629:Estrogen Receptor beta; D010446:Peptide Fragments; D011960:Receptors, Estrogen; D012694:Serine; D000117:Acetylglucosamine