Reactome | LPL hydrolyses TGs from mature CMs

LPL hydrolyses TGs from mature CMs

Stable Identifier

R-HSA-2395768

Type

Reaction [transition]

Species

Homo sapiens

Compartment

extracellular region, plasma membrane

Synonyms

Lipoprotein lipase (LPL) hydrolyses triacylglycerols (TGs) from mature chylomicrons (CM)

ReviewStatus

5/5

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Lipoprotein lipase dimers (LPL:LPL) are tethered to heparan sulfate proteoglycans (HSPG) at endothelial cell surfaces (Fernandez-Borja et al. 1996; Peterson et al. 1992). Both syndecan 1 (Rosenberg et al. 1997) and perlecan (Goldberg 1996) HSPG molecules are capable of tethering LPL. The LPL enzyme catalyzes the hydrolysis and release of triacylglycerols (TG) associated with circulating chylomicrons to leave a CM remnant (CR). This reaction is annotated here as causing the hydrolysis and release of 50 molecules of TG. In vivo, the number is much larger, and TG depletion probably occurs in the course of multiple encounters between a chylomicron and endothelial LPL. This reaction is strongly activated by chylomicron-associated apo C-II protein both in vivo and in vitro (Jackson et al. 1986). Chylomicron-associated apoC-II protein inhibits LPL activity in vitro (Brown and Baginsky 1972), and recent studies have indicated a positive regulatory role for apoA-5 protein, though its molecular mechanism of action remains unclear (Marcais et al. 2005; Merkel and Heeren 2005). CRs can then be taken up by liver parenchymal cells in two ways; 1) directly by the LDL receptor or 2) apoE/HSPG-directed uptake by LDL receptor-related proteins.

Literature References

PubMed ID	Title	Journal	Year
5057882	Inhibition of lipoprotein lipase by an apoprotein of human very low density lipoprotein Brown, WV, Baginsky, ML	Biochem Biophys Res Commun	1972
3942763	Comparison of apolipoprotein C-II-deficient triacylglycerol-rich lipoproteins and trioleoylglycerol/phosphatidylcholine-stabilized particles as substrates for lipoprotein lipase Jackson, RL, Tajima, S, Yamamura, T, Yokoyama, S, Yamamoto, A	Biochim Biophys Acta	1986
16200213	Apoa5 Q139X truncation predisposes to late-onset hyperchylomicronemia due to lipoprotein lipase impairment Marcais, C, Verges, B, Charriere, S, Pruneta, V, Merlin, M, Billon, S, Perrot, L, Drai, J, Sassolas, A, Pennacchio, LA, Fruchart-Najib, J, Fruchart, JC, Durlach, V, Moulin, P	J Clin Invest	2005
1279089	Human lipoprotein lipase: relationship of activity, heparin affinity, and conformation as studied with monoclonal antibodies Peterson, J, Fujimoto, WY, Brunzell, JD	J Lipid Res	1992
8728311	Lipoprotein lipase-mediated uptake of lipoprotein in human fibroblasts: evidence for an LDL receptor-independent internalization pathway Fernandez-Borja, M, Bellido, D, Vilella, E, Olivecrona, G, Vilaro, S	J Lipid Res	1996