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Fly and mammalian lipid phosphate phosphatase isoforms differ in activity both in vitro and in vivo

Camilla Burnett, Ken Howard

Author Affiliations

  1. Camilla Burnett1 and
  2. Ken Howard (ken.howard{at}ucl.ac.uk)*,1
  1. 1 MRC Laboratory for Molecular Cell Biology, and Department of Physiology, University College London, Gower Street, London, WC1E 6BT, UK
  1. * Tel: +44 20 7679 2248; Fax: +44 20 7679 7805; E‐mail: ken.howard{at}ucl.ac.uk

Abstract

Wunen (Wun), a homologue of a lipid phosphate phosphatase (LPP), has a crucial function in the migration and survival of primordial germ cells (PGCs) during Drosophila embryogenesis. Past work has indicated that the LPP isoforms may show functional redundancy in certain systems, and that they have broad‐range lipid phosphatase activities in vitro, with little apparent specificity between them. We show here that there are marked differences in biochemical activity between fly Wun and mammalian LPPs, with Wun having a narrower activity range than has been reported for the mammalian LPPs. Furthermore, although it is active on a range of substrates in vitro, mouse Lpp1 has no activity on an endogenous Drosophila germ‐cell‐specific factor in vivo. Conversely, human LPP3 is active, resulting in aberrant migration and PGC death. These results show an absolute difference in bioactivity among LPP isoforms for the first time in a model organism and may point towards an underlying signalling system that is conserved between flies and humans.

  • Received March 14, 2003.
  • Revision received June 10, 2003.
  • Accepted June 11, 2003.