Mosaic expression of membrane peptidases by confluent cultures of Caco-2 cells.
The cell-surface expression of endopeptidase-24.11 (EC 3.4.24.11) on Caco-2 cells cultured to confluency is markedly heterogeneous unlike that of dipeptidylpeptidase IV (EC 3.4.14.5). Here we have investigated the cell-surface expression of three other ectopeptidases: angiotensin converting enzyme (EC 3.4.15.1), aminopeptidase N (EC 3.4.11.2) and aminopeptidase W (EC 3.4.11.16). We show by indirect immunofluorescent staining that these three enzymes are present on the surface of some cells but not on others. However, these enzymes were detected in the majority of detergent-permeabilised Caco-2 cells indicating the presence of intracellular pools of these enzymes. This suggests that there may either be differential regulation of apical transport for these peptidases or that they recycle at different rates.
Howell
S
S
Department of Biochemistry and Molecular Biology, University of Leeds, UK.
Brewis
I A
IA
Hooper
N M
NM
Kenny
A J
AJ
Turner
A J
AJ
D000626:Aminopeptidases / Q000096:biosynthesis; D018826:CD13 Antigens; D002462:Cell Membrane / Q000201:enzymology* / Q000648:ultrastructure; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000096:biosynthesis; D005455:Fluorescent Antibody Technique; D006801:Humans; D008855:Microscopy, Electron, Scanning; D015260:Neprilysin / Q000096:biosynthesis; D010447:Peptide Hydrolases / Q000096:biosynthesis*; D007703:Peptidyl-Dipeptidase A / Q000096:biosynthesis / Q000648:ultrastructure; D014407:Tumor Cells, Cultured
D010447:Peptide Hydrolases; D000626:Aminopeptidases; C047029:aminopeptidase W; D018826:CD13 Antigens; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4; D007703:Peptidyl-Dipeptidase A; D015260:Neprilysin