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Portrait of Reine Wallenberg. Photo: Kennet Ruona

Reine Wallenberg

Professor, Coordinator Materials Science

Portrait of Reine Wallenberg. Photo: Kennet Ruona

A novel hormone-sensitive lipase isoform expressed in pancreatic beta -cells.

Author

  • Håkan Lindvall
  • Pernilla Nevsten
  • Kristoffer Ström
  • Reine Wallenberg
  • Frank Sundler
  • Dominique Langin
  • Maria Sörhede Winzell
  • Cecilia Holm

Summary, in English

Hormone-sensitive lipase (HSL) is a key enzyme in fatty acid mobilization in many cell types. Two isoforms of HSL are known to date, namely HSLadi (84 kDa in rat) and HSLtes (130 kDa in rat). These are encoded by the same gene, with exons 1-9 encoding the parts that are common to both and an additional 5'-exon encoding the additional amino acids in HSLtes. HSL of various tissues, among these the islet of Langerhans, is larger than HSLadi, but not as large as HSLtes, indicating that there may be other 5'-coding exons. Here we describe the molecular basis for a novel 89-kDa HSL isoform that is expressed in -cells, adipocytes, adrenal glands, and ovaries in the rat and that is encoded by exons 1-9 and exon A, which is spliced to exon 1 and thereby introducing an upstream start codon. The additional 5'-base pairs encode a 43-amino acid peptide, which is highly positively charged. Conglomerates of HSL molecules are in close association with the secretory granules of the -cell, as determined by immunoelectron microscopy with antibodies targeting two separate regions of HSL. We have also determined that the human genomic sequence upstream of exon A has promoter activity in INS-1 cells as well as glucose sensing capability, mediating an increase in expression at high glucose concentration. The minimal promoter is present within 170 bp from the transcriptional start site and maximal glucose responsiveness is conferred by sequence within 850 bp from the transcriptional start site.

Department/s

  • Department of Experimental Medical Science
  • Centre for Analysis and Synthesis
  • Molecular Endocrinology
  • Medicine, Lund

Publishing year

2004

Language

English

Pages

3828-3836

Publication/Series

Journal of Biological Chemistry

Volume

279

Issue

5

Document type

Journal article

Publisher

ASBMB

Topic

  • Cell and Molecular Biology

Status

Published

Research group

  • Molecular Endocrinology

ISBN/ISSN/Other

  • ISSN: 1083-351X