A thumbwheel mechanism for APOA1 activation of LCAT activity in HDL[S]

Allison L. Cooke; Jamie Morris; John T. Melchior; Scott E. Street; W.Gray Jerome; Rong Huang; Andrew B. Herr; Loren E. Smith; Jere P. Segrest; Alan T. Remaley; Amy S. Shah; Thomas B. Thompson; W.Sean Davidson

doi:10.1194/jlr.M085332

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A thumbwheel mechanism for APOA1 activation of LCAT activity in HDL[S]

Journal article

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A thumbwheel mechanism for APOA1 activation of LCAT activity in HDL[S]

Allison L. Cooke, Jamie Morris, John T. Melchior, Scott E. Street, W.Gray Jerome, Rong Huang, Andrew B. Herr, Loren E. Smith, Jere P. Segrest, Alan T. Remaley, …

Journal of lipid research, Vol.59(7), pp.1244-1255

07/01/2018

DOI: 10.1194/jlr.M085332

PMCID: PMC6027914

PMID: 29773713

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Abstract

APOA1 is the most abundant protein in HDL. It modulates interactions that affect HDL';s cardioprotective functions, in part via its activation of the enzyme, LCAT. On nascent discoidal HDL, APOA1 comprises 10 α-helical repeats arranged in an anti-parallel stacked-ring structure that encapsulates a lipid bilayer. Previous chemical cross-linking studies suggested that these APOA1 rings can adopt at least two different orientations, or registries, with respect to each other; however, the functional impact of these structural changes is unknown. Here, we placed cysteine residues at locations predicted to form disulfide bonds in each orientation and then measured APOA1';s ability to adopt the two registries during HDL particle formation. We found that most APOA1 oriented with the fifth helix of one molecule across from fifth helix of the other (5/5 helical registry), but a fraction adopted a 5/2 registry. Engineered HDLs that were locked in 5/5 or 5/2 registries by disulfide bonds equally promoted cholesterol efflux from macrophages, indicating functional particles. However, unlike the 5/5 registry or the WT, the 5/2 registry impaired LCAT cholesteryl esterification activity (P< 0.001), despite LCAT binding equally to all particles. Chemical cross-linking studies suggest that full LCAT activity requires a hybrid epitope composed of helices 5–7 on one APOA1 molecule and helices 3–4 on the other. Thus, APOA1 may use a reciprocating thumbwheel-like mechanism to activate HDL-remodeling proteins.

apolipoprotein A1

apolipoproteins

cholesterol metabolism

cholesterol/efflux

electron microscopy

high density lipoprotein

high density lipoprotein metabolism

lecithin:cholesterol acyltransferase

proteomics

surface plasmon resonance

Details

Title: Subtitle: A thumbwheel mechanism for APOA1 activation of LCAT activity in HDL[S]
Creators: Allison L. Cooke - University of Cincinnati
Jamie Morris - University of Cincinnati
John T. Melchior - University of Cincinnati
Scott E. Street - University of Cincinnati
W.Gray Jerome - Vanderbilt University Medical Center
Rong Huang - University of Cincinnati
Andrew B. Herr - Cincinnati Children's Hospital Medical Center
Loren E. Smith - Vanderbilt University Medical Center
Jere P. Segrest - Vanderbilt University Medical Center
Alan T. Remaley - National Heart Lung and Blood Institute
Amy S. Shah - Cincinnati Children's Hospital Medical Center
Thomas B. Thompson - University of Cincinnati
W.Sean Davidson - University of Cincinnati
Resource Type: Journal article
Publication Details: Journal of lipid research, Vol.59(7), pp.1244-1255
DOI: 10.1194/jlr.M085332
PMID: 29773713
PMCID: PMC6027914
NLM abbreviation: J Lipid Res
ISSN: 0022-2275
eISSN: 1539-7262
Publisher: Elsevier Inc
Number of pages: 12
Grant note: 15PRE25220021; EY08126 / American Heart Association R01 HL127649; P01 HL12803 / National Institutes of Health RR027015; CA68485; DK20593; DK58404; DK59637 / National Institutes of Health
Language: English
Date published: 07/01/2018
Academic Unit: Anesthesia
Record Identifier: 9984949263002771

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