Common sequence variants of lipoprotein lipase: standardized studies of in vitro expression and catalytic function

We have assessed the functional activity of three common sequence variants of human lipoprotein lipase (LPL). Two of these, Asn291Ser and Asp9Asn arise from missense mutations while the third, Ser447Ter, derives from a nonsense mutation, truncating LPL by two residues. As previous in vitro studies h...

Full description

Saved in:
Bibliographic Details
Published in:Biochimica et biophysica acta 1996-07, Vol.1302 (2), p.159-166
Main Authors: Zhang, Hanfang, Henderson, Howard, Gagne, S.Eric, Clee, Susanne M., Miao, Li, Liu, Guoqing, Hayden, Michael R.
Format: Article
Language:English
Subjects:
Catalysis
Cell Line
Cell Membrane - chemistry
DNA - genetics
Enzyme Stability
Gene Expression
Gene variant
Heparin - pharmacology
Humans
Hyperlipidemia
Lipoprotein lipase
Lipoprotein Lipase - chemistry
Lipoprotein Lipase - genetics
Lipoprotein Lipase - metabolism
Macromolecular Substances
Mutation
Proteoglycans - metabolism
Structure-Activity Relationship
Transfection
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We have assessed the functional activity of three common sequence variants of human lipoprotein lipase (LPL). Two of these, Asn291Ser and Asp9Asn arise from missense mutations while the third, Ser447Ter, derives from a nonsense mutation, truncating LPL by two residues. As previous in vitro studies have produced conflicting results, we have re-analyzed the catalytic function of these variants using the COS cell transfection system, under optimized and standardized experimental protocols. We found the Asn291Ser variant to manifest with a decrease in catalytic activity (57% of normal) due to a reduction in secretion and stability of the active homodimeric form. The Asp9Asn variant also showed a significant decrease in catalytic activity (85% of normal), but this was found to be due to a decreased rate of secretion only, as the homodimeric form was stable. The findings for these mutants contrasted with those of the Ser447Ter truncation variant which proved to be catalytically normal; this variant also manifested normal homodimer stability. The truncated variant did however, present with a higher total secreted mass level (131%) than control LPL. This was most likely due to enhanced secretion of the monomeric form. None of these mutations exhibited defects in binding affinity to cell surface proteoglycans. Each of these variants deviated significantly from normal as regards to their secreted activity or mass levels in the COS cell transfection system.
ISSN:0005-2760
0006-3002
1879-145X
DOI:10.1016/0005-2760(96)00059-8