Subcellular localization of the mosquito sterol carrier protein-2 and sterol carrier protein-x.
Subcellular distribution of Aedes aegypti sterol carrier protein-2 (AeSCP-2) and AeSCP-x was studied using electron microscopy. In both cultured A. aegypti cells and in the larval midgut, AeSCP-2 was detected mostly in the cytosol, with some labeling mitochondria and nucleus, but not in membranous vesicles. The widespread distribution of AeSCP-2 in the midgut epithelium is consistent with its potential lipid transfer function in all phases of cholesterol absorption. In contrast, AeSCP-x was found mostly in the peroxisome. Differences in the subcellular distribution of AeSCP-2 and AeSCP-x suggest that these two members of the SCP-2 gene family are functionally distinct. Overexpression of AeSCP-2 in A. aegypti cells showed increased localization of AeSCP-2 to cytosol, mitochondria, and nucleus. This is the first report on the nuclear distribution of an SCP. Overexpression of AeSCP-2 resulted in increased cholesterol incorporation in cells, suggesting that AeSCP-2 enhances cholesterol uptake.
Lan
Que
Q
Department of Entomology, University of Wisconsin-Madison, Madison, WI 53706, USA. qlan@entomology.wisc.edu
Massey
Randall J
RJ
D000330:Aedes / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D000906:Antibodies / Q000276:immunology; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000378:metabolism; D007814:Larva / Q000378:metabolism; D016253:Microscopy, Immunoelectron
D000906:Antibodies; D002352:Carrier Proteins; C072087:sterol carrier proteins