Poster Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

Proteins co-ordinating cell permeability and nutrient transport in the rumen epithelium of sheep. (#437)

Jude J Bond 1 , Karthik S Kamath 2 , Matthew McKay 2 , David Wheeler 3 , Victor H Oddy 1
  1. NSW Department of primary industries, Armidale, NSW, Australia
  2. Department of Molecular Science, Australian proteome analysis facility, Macquarie university, Ryde, NSW, Australia
  3. Orange Agricultural Institute, NSW Department of primary industries, Orange , NSW, Australia

We examined the processes represented by cytosol and membrane rumen epithelial proteins controlling nutrient transport using proteomics.

Ventral rumen tissue from 20 sheep with variation in CH4, CO2 emissions and mean retention time of digesta were used to prepare cytosol and membrane fractions using the method described by Bond et al. (2018). Protein extracts were identified and quantified using SWATH MS using the Ensembl Ovine database. Bioinfomatic tools allocated proteins to their sub-cellular compartments.

We identified 3162 proteins of which 2599 proteins were quantified. Those that control paracellular permeability include 2 claudins (CLDN 1 and 4). We identified 43 plasma membrane solute carrier family (SLC) transporters involved in the transport of inorganic ions, amino acids, lipids, sugars and metabolic intermediates. These are regulated by electrochemical gradients. In addition, 8 ATP-binding cassette (ABC) transporters require ATP for active transport of ions and phospholipids were identified. Nine subunits of the V-ATPase proton pump which acidify intracellular compartments such as the lysosome and phagosome where identified. Transporters identified include a maxi-Cl- anion channel sub-unit and several less well characterised Cl- channels not previously reported in the rumen epithelium. We did not detect any significant difference in the abundance of transporter proteins, or those allocated to cell compartments bound by membranes included endosome, lysosome, exosome, phagosome and peroxisome associated with differences in the sheep sampled.

The in-depth coverage of cytosol and membrane proteins in isolated epithelium has revealed some of the specific proteins which regulate the permeability and transport of nutrients in the rumen epithelium of sheep. It has helped us to assemble a model of the processes regulating nutrient transport that occur in ruminants. Our comprehensive results inform linkage between phenotypes of nutrient use efficiency with cellular protein markers in the rumen epithelium.  

Bond et al. 2019 Journal Animal Science and Biotechnology 10