Acquisition of lipoproteins in the procyclic form of Trypanosoma brucei.
The procyclic form of Trypanosoma brucei binds and internalizes bovine high density lipoprotein (HDL) particles in a saturable process; the binding and uptake of (125)I-labeled HDL are inhibited by excess unlabeled HDL. We calculated that each procyclic trypanosome exposes approximately 1.0 x 10(6) binding sites for bovine HDL, with an equilibrium dissociation constant (Kd) of approximately 1.26 x 10(-7) M. Uptake of HDL particles does not occur at 4 degrees C. At 28 degrees C, a significant amount of the internalized HDL particles were efficiently degraded through a process that is sensitive to the presence of 50 microM chloroquine. These results suggested that the uptake of HDL particles in procyclic T. brucei may occur via receptor mediated endocytosis, leading to proteolytic degradation of the particles in an acidic and endocytic compartment.
Lee
M G
MG
Department of Pathology, New York University Medical Center, NY 10016, USA. leeg02@mcrcr6.med.nyu.edu
Yen
F T
FT
Zhang
Y
Y
Bihain
B E
BE
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003470:Culture Media; D004705:Endocytosis; D006801:Humans; D008075:Lipoproteins, HDL / Q000378:metabolism*; D013696:Temperature; D014346:Trypanosoma brucei brucei / Q000254:growth & development / Q000378:metabolism*
D003470:Culture Media; D008075:Lipoproteins, HDL