3 research outputs found
Proteomic Identification of Common SCF Ubiquitin Ligase FBXO6-Interacting Glycoproteins in Three kinds of Cells
No full textFBOX6 ubiquitin ligase complex is involved in the endoplasmic
reticulum-associated
degradation pathway by mediating the ubiquitination of glycoproteins.
FBXO6 interacts with the chitobiose in unfolded N-glycoprotein, pointing
glycoproteins toward E2 for ubiquitination. Although the glycoprotein-recognizing
mechanism of FBXO6 is well documented, its bona fide interacting glycoproteins are largely unknown. Here we utilized
a protein purification approach combined with LC–MS to systematically
identify the FBXO6-interacting glycoproteins. Following identification
of 39 proteins that specifically interact with FBXO6 in all three
different cell lines, 293T, HeLa and Jurkat cells, we compared the
protein complex organization between wild-type FBXO6 and its mutant,
which fails to recognize glycoproteins. Combining these databases,
29 highly confident glycoproteins that interact with FBXO6 in an N-glycan
dependent manner are identified. Our data provide valuable information
for the discovery of the interacting glycoproteins of FBXO6 and also
demonstrate the potential of these approaches as general platforms
for the global discovery of interacting glycoproteins of other FBAs
(F-box associated regions) containing F-box proteins
Comparison of Molecular Species Distribution of DHA-Containing Triacylglycerols in Milk and Different Infant Formulas by Liquid Chromatography–Mass Spectrometry
No full textLong-chain polyunsaturated fatty
acids (LC-PUFA) are an important
nutritional lipid and have potential in being able to promote human
health. Docosahexaenoic acid (DHA, C22:6ω3) is often added in
infant formulas to meet the nutritional requirement of formula-fed
infants. A comprehensive survey on DHA-containing triacylglycerol
(DHA-TAG) molecular species has been conducted for seven infant formulas
(IFs) sourced from Australia, Europe, and the USA as well as bovine
milk and human milk. Using LC-triple quadrupole MS and LC-LTQ-orbitrap
MS we were able to identify and quantify 56 DHA-TAG species in these
samples; the fatty acid structure of these species was assigned using
their MS2 spectra. The species composition of DHA-TAG was
found to be different between bovine milk, human milk, and IFs and
also between different brands of IFs. Bovine milk and human milk contain
DHA-TAG of smaller molecular size (728–952 Da), whereas five
out of the seven IF samples contain species of broader mass range
(from 728 to 1035 Da). Our study indicates that two types of DHA were
used in the seven IF products surveyed and that there is very large
difference in molecular species distribution in different IF products
that may influence the fine nutritional profile and biological functions
of IF products
