Poster Presentation 23rd Annual Lorne Proteomics Symposium 2018

Proteomic analysis of 4-phenylbutyrate treated HepG2 cells stably expressing ATP-binding cassette transporter A1 (ABCA1) mutants (#73)

Jawaria Munir 1 , Torsten Kleffmann 2 , Sally McCormick 1
  1. Department of Biochemistry, University of Otago, Dunedin, Otago, New Zealand
  2. Centre for Protein Research, Department of Biochemistry, University of Otago, Dunedin, Otago, New Zealand

The ATP-binding cassette A1 (ABCA1) transporter is a cellular membrane protein that exports cellular cholesterol to form high density lipoprotein (HDL) and protect against cardiovascular disease (CVD). Many mutations in ABCA1 disrupt trafficking to the plasma membrane and reduce its function. We previously showed that the chemical chaperone, 4-phenylbutyrate (4-PBA) can restore membrane localisation and increase the cholesterol efflux function of mutant ABCA1s.1 The aim of this study was to identify proteins regulated by 4-PBA that restores ABCA1 localisation. Two ABCA1 mutants (p.T1512M and p.N1800H) expressed in stably transfected HepG2 cells were subject to 4-PBA treatment. The cell lysates were prepared from 4-PBA treated and untreated samples and differentially regulated proteins were analysed by sequential window acquisition of all theoretical fragment ion spectra-MS (SWATH-MS). Proteins showing a >1.5 fold change were subject to bioinformatic analysis using STRING and Panther software packages to categorise their function and potential interactions with ABCA1. This analysis identified a number of trafficking and chaperone proteins including transmembrane protein 33, syntaxin-binding protein 2, transmembrane emp24 domain trafficking protein 2, transmembrane emp24 domain trafficking protein 5 and HSP90 co-chaperone that could assist ABCA1 in restoring its plasma membrane localisation. These proteins warrant further characterisation for their potential to rescue ABCA1 localisation.

  1. Sorrenson, B., Suetani, R. J., Williams, M. J. A., Bickley, V. M., George, P. M., Jones, G. T., & McCormick, S. P. A. (2013). Functional rescue of mutant ABCA1 proteins by sodium 4-phenylbutyrate. Journal of Lipid Research, 54, 55-62.