Assumpta Bennaars-Eiden

Advisor: David Bernlohr, PhD

T32 Support: 2002 - 2003

Education:

1997, B.A., College of St. Catherine, St. Paul, MN
1998 – 2003, Graduate Student, BMBB, University of Minnesota

Project:  Assumpta joined our T32 for the final year of her doctoral work as a result of a developing collaboration between Dr. David Bernlohr (Assumpta’s thesis advisor in BMBB) and Dr David Ingbar focused on novel applications of proteomics to lung cell biology.  She sought to elucidate how fatty acid binding proteins, members of a large multigene family of small cytoplasmic proteins, function to bind hydrophobic molecules and facilitate their movement within the cellular environment.  Analysis of lipolysis in FABP4 [encodes Adipocyte Fatty Acid Binding Protein (A-FABP)] null mice showed a 50% reduction in both basal and stimulated lipolysis. Overexpression of the FABP5 gene encoding (E-FABP) in transgenic mice compared to that of A-FABP in the wild-type mouse led to an increase in lipolysis.  Interestingly, no differences were observed in body weight, fat pad weight or serum-free fatty acid levels.  The molecular composition of the intracellular free fatty acids remained unchanged.  These data indicate that lipolysis correlates with the total level of FABPs and not the specific form expressed.

Her studies identified epithelial fatty acid-binding protein (E-FABP) as a molecular target for 4-HNE modification both in vitro and in vivo.  4-HNE covalently modified (t_1/2 < 60 seconds) E-FABP in vitro as revealed by a combination of MALDI-TOF MS and immunochemical reactivity using antibodies directed to HNE-protein conjugates.  In vitro work identified C120 as the major site of modification, as determined through tandem mass spectral sequencing of tryptic peptides as well as analysis of E-FABP mutants C120A, C127A, and C120A C127A.

Publications:

Bennaars-Eiden A, Higgins LA, Hertzel AV, Kapphahn RJ, Ferrington D, Bernlohr DA. Covalent modification of epithelial fatty acid-binding protein by 4-hydroxynonenal in vitro and in vivo: evidence for a role in antioxidant biology.  Journal of Biological Chemistry  2002; 277:20693-702.

Hertzel AV, Bennaars-Eiden A, Bernlohr DA.  Increased lipolysis in transgenic animals overexpressing the epithelial fatty acid-binding protein in adipose cells.  Journal of Lipid Research  2002; 43:2105-11.

Bernlohr DA, Jenkins AJ, Bennaars-Eiden A.  Adipose tissue and lipid metabolism in biochemistry of lipids, lipoproteins and membranes, IN Vance DE and Vance JE, Eds, Elsevier, Amsterdam/New York, 2002.

Jenkens-Kruchten AE, Bennaars-Eiden A, Ross J, Shen WJ, Kraemer FB, Bernlohr DA.  Fatty acid-binding protein/hormone sensitive lipase interaction; fatty acid dependence on binding. J Biol Chem 2003; 278(48):47636-43.

Brautaset T, Williams MD, Billingham RD, Kaufmann C,  Bennaars AA, Crabber E, Flickinger MC.  Role of the Bacillus methanolicus citrate synthase II gene citY in regulating the secretion of glutamate in L-lysine-secreting mutants.  Applied and Environmental Microbiology.  2003; 69:3986-95.