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Cecilia Holm

Professor

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Quarternary structure and enzymological properties of the different hormone-sensitive lipase (HSL) isoforms.

Author

  • Christian Krintel
  • Cecilia Klint
  • Håkan Lindvall
  • Matthias Mörgelin
  • Cecilia Holm

Summary, in English

BACKGROUND: Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of energy in the form of fatty acids from intracellular stores of neutral lipids. The enzyme has been shown to exist in different isoforms with different molecular masses (84 kDa, 89 kDa and 117 kDa) expressed in a tissue-dependent manner, where the predominant 84 kDa form in adipocytes is the most extensively studied. METHODOLOGY/PRINCIPAL FINDINGS: In this study we employed negative stain electron microscopy (EM) to analyze the quarternary structure of the different HSL isoforms. The results show that all three isoforms adopt a head-to-head homodimeric organization, where each monomer contains two structural domains. We also used enzymatic assays to show that despite the variation in the size of the N-terminal domain all three isoforms exhibit similar enzymological properties with regard to psychrotolerance and protein kinase A (PKA)-mediated phosphorylation and activation. CONCLUSIONS/SIGNIFICANCE: We present the first data on the quaternary structure and domain organization of the three HSL isoforms. We conclude that despite large differences in the size of the N-terminal, non-catalytic domain all three HSL isoforms exhibit the same three-dimensional architecture. Furthermore, the three HSL isoforms are very similar with regard to two unique enzymological characteristics of HSL, i.e., cold adaptation and PKA-mediated activation.

Department/s

  • Medical Structural Biology
  • Molecular Endocrinology
  • Department of Experimental Medical Science
  • Infection Medicine (BMC)
  • EXODIAB: Excellence in Diabetes Research in Sweden

Publishing year

2010

Language

English

Publication/Series

PLoS ONE

Volume

5

Issue

6

Document type

Journal article

Publisher

Public Library of Science

Topic

  • Infectious Medicine
  • Endocrinology and Diabetes

Status

Published

Research group

  • Medical Structural Biology
  • Molecular Endocrinology

ISBN/ISSN/Other

  • ISSN: 1932-6203