Lipoprotein lipase (EC 3.1.1.34) targeting of lipoproteins to receptors.
Summarizing all available data on the role of lipases in targeting lipoproteins to their receptors, we propose the following model: TRL after hydrolysis by LPL have apo E exposed on their surface and might contain one or more molecules of LPL. Both 'apolipoproteins' direct the particles to the cell surface by high-affinity binding to cellular proteoglycans. HL, bound to the surface of hepatocytes can further hydrolyse the particles and together with apo E and LPL mediate the binding to cellular receptors. The most important receptors recognizing these remnants are LRP and VLDLR. The LRP seems to be mainly responsible for the hepatic uptake of remnant lipoproteins, while the VLDLR, mainly located in adipose tissue and muscle, might target the lipoproteins to these tissues for fatty acid delivery.
Beisiegel
U
U
Medical Clinic, University Hospital Eppendorf, Hamburg, Germany.
Heeren
J
J
D006801:Humans; D006868:Hydrolysis; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism; D011973:Receptors, LDL / Q000378:metabolism; D018110:Receptors, Lipoprotein / Q000378:metabolism*
D008074:Lipoproteins; D011509:Proteoglycans; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; D008071:Lipoprotein Lipase