Characterization of the LDL receptor in rat promegakaryoblasts in culture.
Rat promegakaryoblasts (RPM, a precursor platelet cell line) in culture exhibited a capacity to bind, take up and degrade 125I-LDL. The low density lipoprotein (LDL) binding showed the following characteristics: (a) high affinity, (b) saturability, (c) specificity, (d) down-regulation, after exposure to 25 hydroxycholesterol. Furthermore the proteolytic degradation of 125I-LDL by RPMs was inhibited by chloroquine which interferes with the lysosomal degradation processes. These findings show LDL receptor cell biology of RPM to be of the classical type and to differ from that of platelets.
Budd
T J
TJ
Department of Biochemistry, University of Nottingham Medical School, Queen's Medical Centre, UK.
Hemming
F W
FW
Middleton
B
B
D000818:Animals; D001854:Bone Marrow Cells; D002460:Cell Line; D002738:Chloroquine / Q000494:pharmacology; D006888:Hydroxycholesterols / Q000494:pharmacology; D007700:Kinetics; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008533:Megakaryocytes / Q000187:drug effects / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011973:Receptors, LDL / Q000378:metabolism*
D006888:Hydroxycholesterols; D008077:Lipoproteins, LDL; D011973:Receptors, LDL; C007997:25-hydroxycholesterol; D002738:Chloroquine