Abetalipoproteinemia; Apolipoprotein B-100; Biochemistry; Blotting, Western; Cell Biology; Cell Fractionation; Electrophoresis; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Endoplasmic Reticulum-Associated Degradation; Immunoprecipitation; Lipoproteins; Microscopy, Fluorescence; Molecular Biology; Molecular Chaperones; Protein Folding; Quality Control
ER quality control and ER-associated degradation
We are interested in the molecular characterization of a quality control system that operates in the endoplasmic reticulum (ER) to ensure that only properly folded proteins will be released. Misfolded polypeptides are retro-translocated from the ER to the cytosol, where they become poly-ubiquitinated and destructed by proteasomes. ER-associated degradation (ERAD) is of relevance for a variety of genetically inherited, neurodegenerative, and virally transmitted diseases with protein folding defects.
The role of MTP and PDI in the assembly and secretion of atherogenic lipoprotein particles
Microsomal triglyceride transfer protein (MTP) is a lipid transfer protein required for the assembly and secretion of very low density lipoproteins (VLDL). Active MTP is a heterodimer containing a 97 kDa catalytic subunit and a 58 kDa subunit identified as protein disulfide isomerase (PDI). The MTP complex catalyzes the loading of apolipoprotein B (apoB) with lipids and/or the translocation of apoB into the lumen of the endoplasmic reticulum (ER). In avians, the synthesis of VLDL is inducible by estrogen. We are studying the effect of estrogen treatment on MTP activity and on the regulation of VLDL secretion that is also determined by lipid availability and apoB degradation.
- Estrogen enhances secretion of apolipoprotein B-100 containing lipoproteins by BeWo cells. Kamper M, Manns CC, Plieschnig JA, Schneider WJ, Ivessa NE, Hermann M. Biochimie. 2015 May;112:121-8. doi: 10.1016/j.biochi.2015.03.002. Epub 2015 Mar 10. PMID: 25765953
- Expression of microsomal triglyceride transfer protein in lipoprotein-synthesizing tissues of the developing chicken embryo. Eresheim C, Plieschnig J, Ivessa NE, Schneider WJ, Hermann M. Biochimie. 2014 Jun;101:67-74. doi: 10.1016/j.biochi.2013.12.020. Epub 2014 Jan 4. PMID: 24394625
- Molecular cloning, expression, and hormonal regulation of the chicken microsomal triglyceride transfer protein. Ivessa NE, Rehberg E, Kienzle B, Seif F, Hermann R, Hermann M, Schneider WJ, Gordon DA. Gene. 2013 Jul 1;523(1):1-9. doi: 10.1016/j.gene.2013.03.102. Epub 2013 Mar 29. PMID: 23542778
- Processing of N-linked glycans during endoplasmic-reticulum-associated degradation of a short-lived variant of ribophorin I. Kitzmüller C, Caprini A, Moore SE, Frenoy JP, Schwaiger E, Kellermann O, Ivessa NE, Ermonval M. Biochem J. 2003 Dec 15;376(Pt 3):687-96. PMID: 12952521
- N-glycan structure of a short-lived variant of ribophorin I expressed in the MadIA214 glycosylation-defective cell line reveals the role of a mannosidase that is not ER mannosidase I in the process of glycoprotein degradation. Ermonval M, Kitzmüller C, Mir AM, Cacan R, Ivessa NE. Glycobiology. 2001 Jul;11(7):565-76. PMID: 11447136