Proteomics of the hydrolases of the vertebrate intestinal brush border membrane

ANTONIO BRUN; GREGORY A. BARRETT-WILT; KARASOV, WILLIAM H.; CAVIEDES-VIDAL E

Salzburg

Congreso; Annual Meeting SEB; 2018

At the intestine?s apical brush border membrane (bbm), enzyme hydrolysis precedes nutrient absorption. The study of the activities of the intestinal enzymes across different taxa, and of their phenotypic plasticity under different ecological scenarios, has produced general adaptive/evolutionary patterns that have received a good amount of attention. Recently, the study of gene expressions underlying changes in enzyme activities has become increasingly possible, but knowledge about the level of expression of the hydrolases at the bbm is still scarce. Therefore, we studied the relative abundance of intestinal enzymes in bbm of three birds, the strictly granivorous Taeniopygia guttata, the granivorous/omnivorous Gallus gallus, the insectivorous Sturnus vulgaris and two model rodents, the omnivores Mus musculus and Rattus norvergicus. We predicted that proteases and lipases would be proportionally more abundant in an insectivore, and carbohydrases proportionally more abundant in starch consumers. Intestinal tissue of four individuals of each species were harvested, enterocytes isolated and bbm isolates prepared. Proteins were solubilized, digested and chromatographically separated. Peptides were analyzed by nanoLC-MS/MS. Raw MS/MS data were converted and used to search against Uniprot and RefSeq amino acid sequence databases. Hydrolases (i.e., their spectra) represented between 4 and 11% of the total protein (i.e., total spectra) detected. Intestinal hydrolases were grouped in four categories, carbohydrases, proteases, lipases, phosphatases and nucleases. In agreement with our prediction S. vulgaris had a higher proportion of intestinal proteases and lipases and less carbohydrases than granivorous/omnivorous species. Supported by NSF IOS-1354893&CONICET PIP-0814.