Expression of the alpha subunit of PABA peptide hydrolase (EC 3.4.24.18) in MDCK cells. Synthesis and secretion of an enzymatically inactive homodimer.
In this paper, we report the expression of PPH alpha in the polarized cell line MDCK (Madin Darby canine kidney). In these cells, the enzyme was synthesized in an inactive proform, which upon treatment with trypsin was activated. The enzyme isolated from cell extracts was core-glycosylated and appeared to be retained in the ER as a homodimer. No PPH alpha was detectable on the surface of intact cells by immunofluorescence. However, a complex glycosylated soluble but inactive form was present in the culture medium, suggesting that proteolytic removal of the C-terminal membrane anchoring peptide leads to the secretion of PPH alpha.
Grünberg
J
J
Institute of Biochemistry and Molecular Biology, University of Berne, Switzerland.
Dumermuth
E
E
Eldering
J A
JA
Sterchi
E E
EE
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003470:Culture Media; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D008666:Metalloendopeptidases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D012995:Solubility; D014162:Transfection; D014357:Trypsin
D003470:Culture Media; D004792:Enzyme Precursors; D014357:Trypsin; D008666:Metalloendopeptidases; C053833:meprin A