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Decreased UDP‐GlcNAc levels abrogate proliferation control in EMeg32‐deficient cells
Author(s) -
Boehmelt Guido,
Wakeham Andrew,
Elia Andrew,
Sasaki Takehiko,
Plyte Sue,
Potter Julia,
Yang Yingju,
Tsang Eric,
Ruland Jürgen,
Iscove Norman N.,
Dennis James W.,
Mak Tak W.
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.19.5092
Subject(s) - biology , microbiology and biotechnology , embryonic stem cell , cytosol , intracellular , cell growth , phosphorylation , golgi apparatus , biochemistry , enzyme , gene , endoplasmic reticulum
The hexosamine pathway provides UDP‐ N ‐acetylhexosamine donor substrates used in cytosolic and Golgi‐mediated glycosylation of proteins and for formation of glycosylphosphatidylinositol (GPI) anchors, which tether proteins to the outer plasma membrane. We have recently identified the murine glucosamine‐6‐phosphate (GlcN6P) acetyltransferase, EMeg32, as a developmentally regulated enzyme on the route to UDP‐ N ‐acetylglucosamine (UDP‐GlcNAc). Here we describe embryos and cells that have the EMeg32 gene inactivated by homologous recombination. Homozygous mutant embryos die at around embryonic day (E) 7.5 with a general proliferative delay of development. In vitro differentiated EMeg32 −/− ES cells show reduced proliferation. Mouse embryonic fibroblasts (MEFs) deficient for EMeg32 exhibit defects in proliferation and adhesiveness, which could be complemented by stable re‐expression of EMeg32 or by nutritional restoration of intracellular UDP‐GlcNAc levels. Reduced UDP‐GlcNAc levels predominantly translated into decreased O ‐GlcNAc modifications of cytosolic and nuclear proteins. Interestingly, growth‐impaired EMeg32 −/− MEFs withstand a number of apoptotic stimuli and express activated PKB/AKT. Thus, EMeg32‐dependent UDP‐GlcNAc levels influence cell cycle progression and susceptibility to apoptotic stimuli.