Biosynthesis of intestinal microvillar proteins. Forskolin reduces surface expression of aminopeptidase N
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Biosynthesis of intestinal microvillar proteins. Forskolin reduces surface expression of aminopeptidase N. / Danielsen, E M; Hansen, Gert Helge; Cowell, G M.
I: European Journal of Cell Biology, Bind 44, Nr. 2, 1987, s. 273-7.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Biosynthesis of intestinal microvillar proteins. Forskolin reduces surface expression of aminopeptidase N
AU - Danielsen, E M
AU - Hansen, Gert Helge
AU - Cowell, G M
N1 - Keywords: Aminopeptidases; Animals; Antigens, CD13; Biological Transport; Endoplasmic Reticulum; Forskolin; Golgi Apparatus; Intestinal Mucosa; Intestine, Small; Microscopy, Electron; Microvilli; Organ Culture Techniques; Swine
PY - 1987
Y1 - 1987
N2 - The effect of forskolin on the biosynthesis and intracellular transport of pig intestinal aminopeptidase N (EC 3.4.11.2) was studied in organ cultured mucosal explants. The drug which activates adenylate cyclase and hence the cAMP-dependent glycogenolytic pathway did not affect the explant content nor microvillar enrichment of the enzyme. Forskolin, however, caused a decrease in the microvillar expression of aminopeptidase N which developed in a time-dependent manner from about 40% by 80 min to 80% by 4 h of labeling. The intracellular pool size of the transient, high mannose glycosylated form of aminopeptidase N was unaffected by forskolin, indicating a normal synthesis in the rough endoplasmic reticulum. The decrease in surface expression is therefore caused by an induced posttranslational degradation of the enzyme, most likely taking place in the Golgi complex. The degradatory effect on newly synthesized aminopeptidase N was not accompanied by any morphological alterations of the enterocyte; in particular, the microvillar membrane appeared entirely unaffected by forskolin. The results obtained provide evidence for the existence of a posttranslational mechanism, whereby a polarized cell is capable of regulating its expression of apical proteins.
AB - The effect of forskolin on the biosynthesis and intracellular transport of pig intestinal aminopeptidase N (EC 3.4.11.2) was studied in organ cultured mucosal explants. The drug which activates adenylate cyclase and hence the cAMP-dependent glycogenolytic pathway did not affect the explant content nor microvillar enrichment of the enzyme. Forskolin, however, caused a decrease in the microvillar expression of aminopeptidase N which developed in a time-dependent manner from about 40% by 80 min to 80% by 4 h of labeling. The intracellular pool size of the transient, high mannose glycosylated form of aminopeptidase N was unaffected by forskolin, indicating a normal synthesis in the rough endoplasmic reticulum. The decrease in surface expression is therefore caused by an induced posttranslational degradation of the enzyme, most likely taking place in the Golgi complex. The degradatory effect on newly synthesized aminopeptidase N was not accompanied by any morphological alterations of the enterocyte; in particular, the microvillar membrane appeared entirely unaffected by forskolin. The results obtained provide evidence for the existence of a posttranslational mechanism, whereby a polarized cell is capable of regulating its expression of apical proteins.
M3 - Journal article
C2 - 2891508
VL - 44
SP - 273
EP - 277
JO - Cytobiologie
JF - Cytobiologie
SN - 0724-5130
IS - 2
ER -
ID: 9748598