Identification of the non-specific lipid-transfer protein (sterol carrier protein 2) in peroxisomes of lung type II cells.
In view of the proposed role of the non-specific lipid-transfer protein (nsL-TP; sterol carrier protein 2) in the metabolism of pulmonary surfactant lipids (Batenburg et al. (1994) Biochem. J. 298, 223-229), its subcellular localization was studied in the surfactant producing alveolar type II cells. It was shown by immuno-electron microscopy that nsL-TP colocalizes with the peroxisomal marker catalase. The peroxisomal localization of nsL-TP was confirmed by gradient fractionation of type II cell homogenates. As a peroxisomal marker acyl-CoA:dihydroxyacetone-phosphate acyltransferase was assayed. Given this subcellular localization, it is very unlikely that nsL-TP plays a role in the transfer of surfactant lipids from the endoplasmic reticulum to the lamellar bodies. These results strengthen the opinion that peroxisomes are involved in surfactant synthesis.
Ossendorp
B C
BC
Laboratory of Veterinary Biochemistry, Utrecht University, The Netherlands.
Voorhout
W F
WF
van Golde
L M
LM
Wirtz
K W
KW
Batenburg
J J
JJ
D000217:Acyltransferases / Q000378:metabolism; D000818:Animals; D015415:Biomarkers; D002352:Carrier Proteins / Q000378:metabolism*; D008297:Male; D008830:Microbodies / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D010940:Plant Proteins; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013261:Sterols / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
D015415:Biomarkers; D002352:Carrier Proteins; D010940:Plant Proteins; D011663:Pulmonary Surfactants; D013261:Sterols; C072087:sterol carrier proteins; D000217:Acyltransferases; C020051:glycerone-phosphate O-acyltransferase