Lipoprotein lipase is active as a monomer

Anne P Beigneux; Christopher M Allan; Norma P Sandoval; Geoffrey W Cho; Patrick J Heizer; Rachel S Jung; Kimber L Stanhope; Peter J Havel; Gabriel Birrane; Muthuraman Meiyappan; John E Gill; Masami Murakami; Kazuya Miyashita; Katsuyuki Nakajima; Michael Ploug; Loren G Fong; Stephen G Young

doi:10.1073/pnas.1900983116

Lipoprotein lipase is active as a monomer

Anne P Beigneux, Christopher M Allan, Norma P Sandoval, Geoffrey W Cho, Patrick J Heizer, Rachel S Jung, Kimber L Stanhope, Peter J Havel, Gabriel Birrane, Muthuraman Meiyappan, John E Gill, Masami Murakami, Kazuya Miyashita, Katsuyuki Nakajima, Michael Ploug, Loren G Fong, Stephen G Young

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Abstract

Lipoprotein lipase (LPL), the enzyme that hydrolyzes triglycerides in plasma lipoproteins, is assumed to be active only as a homodimer. In support of this idea, several groups have reported that the size of LPL, as measured by density gradient ultracentrifugation, is ∼110 kDa, twice the size of LPL monomers (∼55 kDa). Of note, however, in those studies the LPL had been incubated with heparin, a polyanionic substance that binds and stabilizes LPL. Here we revisited the assumption that LPL is active only as a homodimer. When freshly secreted human LPL (or purified preparations of LPL) was subjected to density gradient ultracentrifugation (in the absence of heparin), LPL mass and activity peaks exhibited the size expected of monomers (near the 66-kDa albumin standard). GPIHBP1-bound LPL also exhibited the size expected for a monomer. In the presence of heparin, LPL size increased, overlapping with a 97.2-kDa standard. We also used density gradient ultracentrifugation to characterize the LPL within the high-salt and low-salt peaks from a heparin-Sepharose column. The catalytically active LPL within the high-salt peak exhibited the size of monomers, whereas most of the inactive LPL in the low-salt peak was at the bottom of the tube (in aggregates). Consistent with those findings, the LPL in the low-salt peak, but not that in the high-salt peak, was easily detectable with single mAb sandwich ELISAs, in which LPL is captured and detected with the same antibody. We conclude that catalytically active LPL can exist in a monomeric state.

Original language	English
Journal	Proceedings of the National Academy of Sciences of the United States of America
Volume	116
Issue number	13
Pages (from-to)	6319-6328
Number of pages	10
ISSN	0027-8424
DOIs	https://doi.org/10.1073/pnas.1900983116
Publication status	Published - 2019

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Beigneux, A. P., Allan, C. M., Sandoval, N. P., Cho, G. W., Heizer, P. J., Jung, R. S., Stanhope, K. L., Havel, P. J., Birrane, G., Meiyappan, M., Gill, J. E., Murakami, M., Miyashita, K., Nakajima, K., Ploug, M., Fong, L. G., & Young, S. G. (2019). Lipoprotein lipase is active as a monomer. Proceedings of the National Academy of Sciences of the United States of America, 116(13), 6319-6328. https://doi.org/10.1073/pnas.1900983116

Beigneux, AP, Allan, CM, Sandoval, NP, Cho, GW, Heizer, PJ, Jung, RS, Stanhope, KL, Havel, PJ, Birrane, G, Meiyappan, M, Gill, JE, Murakami, M, Miyashita, K, Nakajima, K, Ploug, M, Fong, LG & Young, SG 2019, 'Lipoprotein lipase is active as a monomer', Proceedings of the National Academy of Sciences of the United States of America, vol. 116, no. 13, pp. 6319-6328. https://doi.org/10.1073/pnas.1900983116

@article{07203a55919b447690165acb0229aa07,

title = "Lipoprotein lipase is active as a monomer",

abstract = "Lipoprotein lipase (LPL), the enzyme that hydrolyzes triglycerides in plasma lipoproteins, is assumed to be active only as a homodimer. In support of this idea, several groups have reported that the size of LPL, as measured by density gradient ultracentrifugation, is ∼110 kDa, twice the size of LPL monomers (∼55 kDa). Of note, however, in those studies the LPL had been incubated with heparin, a polyanionic substance that binds and stabilizes LPL. Here we revisited the assumption that LPL is active only as a homodimer. When freshly secreted human LPL (or purified preparations of LPL) was subjected to density gradient ultracentrifugation (in the absence of heparin), LPL mass and activity peaks exhibited the size expected of monomers (near the 66-kDa albumin standard). GPIHBP1-bound LPL also exhibited the size expected for a monomer. In the presence of heparin, LPL size increased, overlapping with a 97.2-kDa standard. We also used density gradient ultracentrifugation to characterize the LPL within the high-salt and low-salt peaks from a heparin-Sepharose column. The catalytically active LPL within the high-salt peak exhibited the size of monomers, whereas most of the inactive LPL in the low-salt peak was at the bottom of the tube (in aggregates). Consistent with those findings, the LPL in the low-salt peak, but not that in the high-salt peak, was easily detectable with single mAb sandwich ELISAs, in which LPL is captured and detected with the same antibody. We conclude that catalytically active LPL can exist in a monomeric state.",

author = "Beigneux, {Anne P} and Allan, {Christopher M} and Sandoval, {Norma P} and Cho, {Geoffrey W} and Heizer, {Patrick J} and Jung, {Rachel S} and Stanhope, {Kimber L} and Havel, {Peter J} and Gabriel Birrane and Muthuraman Meiyappan and Gill, {John E} and Masami Murakami and Kazuya Miyashita and Katsuyuki Nakajima and Michael Ploug and Fong, {Loren G} and Young, {Stephen G}",

note = "Copyright {\textcopyright} 2019 the Author(s). Published by PNAS.",

year = "2019",

doi = "10.1073/pnas.1900983116",

language = "English",

volume = "116",

pages = "6319--6328",

journal = "Proceedings of the National Academy of Sciences of the United States of America",

issn = "0027-8424",

publisher = "The National Academy of Sciences of the United States of America",

number = "13",

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TY - JOUR

T1 - Lipoprotein lipase is active as a monomer

AU - Beigneux, Anne P

AU - Allan, Christopher M

AU - Sandoval, Norma P

AU - Cho, Geoffrey W

AU - Heizer, Patrick J

AU - Jung, Rachel S

AU - Stanhope, Kimber L

AU - Havel, Peter J

AU - Birrane, Gabriel

AU - Meiyappan, Muthuraman

AU - Gill, John E

AU - Murakami, Masami

AU - Miyashita, Kazuya

AU - Nakajima, Katsuyuki

AU - Ploug, Michael

AU - Fong, Loren G

AU - Young, Stephen G

PY - 2019

Y1 - 2019

N2 - Lipoprotein lipase (LPL), the enzyme that hydrolyzes triglycerides in plasma lipoproteins, is assumed to be active only as a homodimer. In support of this idea, several groups have reported that the size of LPL, as measured by density gradient ultracentrifugation, is ∼110 kDa, twice the size of LPL monomers (∼55 kDa). Of note, however, in those studies the LPL had been incubated with heparin, a polyanionic substance that binds and stabilizes LPL. Here we revisited the assumption that LPL is active only as a homodimer. When freshly secreted human LPL (or purified preparations of LPL) was subjected to density gradient ultracentrifugation (in the absence of heparin), LPL mass and activity peaks exhibited the size expected of monomers (near the 66-kDa albumin standard). GPIHBP1-bound LPL also exhibited the size expected for a monomer. In the presence of heparin, LPL size increased, overlapping with a 97.2-kDa standard. We also used density gradient ultracentrifugation to characterize the LPL within the high-salt and low-salt peaks from a heparin-Sepharose column. The catalytically active LPL within the high-salt peak exhibited the size of monomers, whereas most of the inactive LPL in the low-salt peak was at the bottom of the tube (in aggregates). Consistent with those findings, the LPL in the low-salt peak, but not that in the high-salt peak, was easily detectable with single mAb sandwich ELISAs, in which LPL is captured and detected with the same antibody. We conclude that catalytically active LPL can exist in a monomeric state.

AB - Lipoprotein lipase (LPL), the enzyme that hydrolyzes triglycerides in plasma lipoproteins, is assumed to be active only as a homodimer. In support of this idea, several groups have reported that the size of LPL, as measured by density gradient ultracentrifugation, is ∼110 kDa, twice the size of LPL monomers (∼55 kDa). Of note, however, in those studies the LPL had been incubated with heparin, a polyanionic substance that binds and stabilizes LPL. Here we revisited the assumption that LPL is active only as a homodimer. When freshly secreted human LPL (or purified preparations of LPL) was subjected to density gradient ultracentrifugation (in the absence of heparin), LPL mass and activity peaks exhibited the size expected of monomers (near the 66-kDa albumin standard). GPIHBP1-bound LPL also exhibited the size expected for a monomer. In the presence of heparin, LPL size increased, overlapping with a 97.2-kDa standard. We also used density gradient ultracentrifugation to characterize the LPL within the high-salt and low-salt peaks from a heparin-Sepharose column. The catalytically active LPL within the high-salt peak exhibited the size of monomers, whereas most of the inactive LPL in the low-salt peak was at the bottom of the tube (in aggregates). Consistent with those findings, the LPL in the low-salt peak, but not that in the high-salt peak, was easily detectable with single mAb sandwich ELISAs, in which LPL is captured and detected with the same antibody. We conclude that catalytically active LPL can exist in a monomeric state.

U2 - 10.1073/pnas.1900983116

DO - 10.1073/pnas.1900983116

M3 - Journal article

C2 - 30850549

SN - 0027-8424

VL - 116

SP - 6319

EP - 6328

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 13

ER -

Lipoprotein lipase is active as a monomer

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