LMF1,2 transport LIPC dimer from ER lumen to extracellular region

Stable Identifier
Reaction [omitted]
Homo sapiens
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Hepatic triacylglycerol lipase (LIPC, and lipoprotein lipase, LPL) are dimeric lipases (Hill et al. 1997) that hydrolyse triglycerides from circulating lipoproteins thereby playing important roles in lipoprotein remodeling and uptake. LIPC dimer (as well as LPL dimer) binds to an ER membrane protein known as lipase maturation factor 1 (LMF1) which can mediate secretion and enzymatic maturation of these lipases. Human LMF1 contain five TM segments that divide the protein into six separate domains with cytoplasmic and ER lumenal orientation thereby transporting LIPC dimer from ER lumen to the cytosol. The mechanism of LIPC dimer translocation from cytosol to secretion is unknown (Doolittle et al. 2009, Babilonia-Rosa & Neher 2014). Another family member, LMF2, may function as LMF1 based on similarity. Defects in LMF1 can cause combined lipase deficiency (CLD; MIM:246650), characterised by hypertriglyceridemia caused by ER retention of both LIPC dimer and LPL dimer (Peterfy et al. 2007).

Literature References
PubMed ID Title Journal Year
19783858 Lipase maturation factor LMF1, membrane topology and interaction with lipase proteins in the endoplasmic reticulum

Yin, F, Walter, P, Wong, H, Neher, SB, Ben-Zeev, O, Hosseini, M, Ling-Liao, J, Doolittle, MH, Péterfy, M, Gallagher, CM

J. Biol. Chem. 2009
24909692 Purification, cellular levels, and functional domains of lipase maturation factor 1

Babilonia-Rosa, MA, Neher, SB

Biochem. Biophys. Res. Commun. 2014
17994020 Mutations in LMF1 cause combined lipase deficiency and severe hypertriglyceridemia

Malloy, MJ, Weissglas-Volkov, D, Reue, K, Aouizerat, BE, Mao, HZ, Pajukanta, P, Frost, PH, Kane, JP, Ben-Zeev, O, Doolittle, MH, Pullinger, CR, Péterfy, M

Nat. Genet. 2007
9379936 Hepatic lipase: high-level expression and subunit structure determination

Davis, RC, Wong, H, Schotz, MC, Hill, JS, Yang, D

Meth. Enzymol. 1997
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