Visualization of the uptake of individual HDL particles in living cells via the scavenger receptor class B type I.
The scavenger receptor class B type I (SR-BI) plays an important role in mediating selective uptake of high-density lipoprotein (HDL)-derived cholesterol and cholesteryl ester in liver and steroidogenic tissues. The molecular mechanism by which this receptor mediates selective cholesteryl ester uptake remains still enigmatic. We applied ultrasensitive fluorescence microscopy to visualize the intracellular transport routes of HDL particles taken up via SR-BI in a Chinese hamster ovarian cell line. Although diffusion of the receptor bound particles on the cell surface is slow, internalization is accompanied by a dramatic increase in the mobility of the particles. HDL particles are endocytosed as clusters and actively transported to the perinuclear region of the cell. Costaining with organelle markers confirmed the involvement of an acidic compartment and the Golgi apparatus in the uptake process; finally, resecretion of the HDL particles was observed.
Rhode
Sebastian
S
Institute for Biophysics, University of Linz, Altenbergerstr.69, A-4040 Linz, Austria.
Breuer
Anton
A
Hesse
Jan
J
Sonnleitner
Max
M
Pagler
Tamara A
TA
Doringer
Marlon
M
Schütz
Gerhard J
GJ
Stangl
Herbert
H
D000818:Animals; D018955:CD36 Antigens / Q000378:metabolism*; D016466:CHO Cells; D002788:Cholesterol Esters / Q000737:chemistry; D006224:Cricetinae; D003412:Cricetulus; D004705:Endocytosis; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008075:Lipoproteins, HDL / Q000378:metabolism* / Q000493:pharmacokinetics; D008099:Liver / Q000378:metabolism; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D013256:Steroids / Q000378:metabolism
D018955:CD36 Antigens; D002788:Cholesterol Esters; D008075:Lipoproteins, HDL; D013256:Steroids