TY - JOUR
T1 - Basolateral secretion of amyloid precursor protein in Madin-Darby canine kidney cells is disturbed by alterations of intracellular pH and by introducing a mutation associated with familial Alzheimer's disease
AU - De Strooper, Bart
AU - Craessaerts, Katleen
AU - Dewachter, Ilse
AU - Moechars, Dieder
AU - Greenberg, Barry
AU - Van Leuven, Fred
AU - Van Den Berghe, Herman
PY - 1995/2/24
Y1 - 1995/2/24
N2 - The analysis of potential sorting signals in amyloid precursor protein (APP) by site-directed mutagenesis and the disturbance of metabolic pathways by drugs is used here to define the parameters that determine polarized secretion of APP in Madin-Darby canine kidney cells. Endogenously produced APP751/770 and APP695 produced from transfected constructs are secreted almost exclusively into the basolateral compartment. The sorting mechanism is highly dependent on intracellular pH as demonstrated by its sensitivity to primary amines and inhibitors of the acidifying vacuolar proton ATPase. The role of potential basolateral sorting signals in the cytoplasmic, transmembrane, and βA4 amyloid region of APP was investigated. Neither deletion of the endocytosis and putative basolateral sorting signal GY.NPTY nor complete deletion of the cytoplasmic domain causes apical secretion of soluble APP. Further deletion of the transmembrane domain and of the βA4 amyloid region confirmed that the major basolateral sorting determinant resides in the extracellular domain of APP. Increased β-secretase cleavage of APP after introduction of the "swedish" double mutation causes apical missorting of about 20% of β-secretase-cleaved APP. The data underline the complexity of processing and sorting APP in polarized cells and suggest a possible problem of protein sorting in Alzheimer's Disease.
AB - The analysis of potential sorting signals in amyloid precursor protein (APP) by site-directed mutagenesis and the disturbance of metabolic pathways by drugs is used here to define the parameters that determine polarized secretion of APP in Madin-Darby canine kidney cells. Endogenously produced APP751/770 and APP695 produced from transfected constructs are secreted almost exclusively into the basolateral compartment. The sorting mechanism is highly dependent on intracellular pH as demonstrated by its sensitivity to primary amines and inhibitors of the acidifying vacuolar proton ATPase. The role of potential basolateral sorting signals in the cytoplasmic, transmembrane, and βA4 amyloid region of APP was investigated. Neither deletion of the endocytosis and putative basolateral sorting signal GY.NPTY nor complete deletion of the cytoplasmic domain causes apical secretion of soluble APP. Further deletion of the transmembrane domain and of the βA4 amyloid region confirmed that the major basolateral sorting determinant resides in the extracellular domain of APP. Increased β-secretase cleavage of APP after introduction of the "swedish" double mutation causes apical missorting of about 20% of β-secretase-cleaved APP. The data underline the complexity of processing and sorting APP in polarized cells and suggest a possible problem of protein sorting in Alzheimer's Disease.
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U2 - 10.1074/jbc.270.8.4058
DO - 10.1074/jbc.270.8.4058
M3 - Article
C2 - 7876155
AN - SCOPUS:0028906488
SN - 0021-9258
VL - 270
SP - 4058
EP - 4065
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 8
ER -