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Gene organization and primary structure of human hormone-sensitive lipase: possible significance of a sequence homology with a lipase of Moraxella TA144, an antarctic bacterium

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Author

  • Dominique Langin
  • Henrik Laurell
  • Lena Stenson
  • Per Belfrage
  • Cecilia Holm

Summary, in English

The human hormone-sensitive lipase (HSL) gene encodes a 786-aa polypeptide (85.5 kDa). It is composed of nine exons spanning approximately 11 kb, with exons 2-5 clustered in a 1.1-kb region. The putative catalytic site (Ser423) and a possible lipid-binding region in the C-terminal part are encoded by exons 6 and 9, respectively. Exon 8 encodes the phosphorylation site (Ser551) that controls cAMP-mediated activity and a second site (Ser553) that is phosphorylated by 5'-AMP-activated protein kinase. Human HSL showed 83% identity with the rat enzyme and contained a 12-aa deletion immediately upstream of the phosphorylation sites with an unknown effect on the activity control. Besides the catalytic site motif (Gly-Xaa-Ser-Xaa-Gly) found in most lipases, HSL shows no homology with other known lipases or proteins, except for a recently reported unexpected homology between the region surrounding its catalytic site and that of the lipase 2 of Moraxella TA144, an antarctic psychrotrophic bacterium. The gene of lipase 2, which catalyses lipolysis below 4 degrees C, was absent in the genomic DNA of five other Moraxella strains living at 37 degrees C. The lipase 2-like sequence in HSL may reflect an evolutionarily conserved cold adaptability that might be of critical survival value when low-temperature-mobilized endogenous lipids are the primary energy source (e.g., in poikilotherms or hibernators). The finding that HSL at 10 degrees C retained 3- to 5-fold more of its 37 degrees C catalytic activity than lipoprotein lipase or carboxyl ester lipase is consistent with this hypothesis.

Publishing year

1993

Language

English

Pages

4897-4901

Publication/Series

Proceedings of the National Academy of Sciences

Volume

90

Issue

11

Document type

Journal article

Publisher

National Academy of Sciences

Topic

  • Endocrinology and Diabetes

Status

Published

Research group

  • Insulin Signal Transduction
  • Molecular Endocrinology

ISBN/ISSN/Other

  • ISSN: 1091-6490