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Membrane localization of cyclic nucleotide phosphodiesterase 3 (PDE3). Two N-terminal domains are required for the efficient targeting to, and association of, PDE3 with endoplasmic reticulum

Author:
  • Y Shakur
  • K Takeda
  • Y Kenan
  • Z X Yu
  • G Rena
  • D Brandt
  • M D Houslay
  • Eva Degerman
  • V J Ferrans
  • V C Manganiello
Publishing year: 2000
Language: English
Pages: 38749-38761
Publication/Series: Journal of Biological Chemistry
Volume: 275
Issue: 49
Document type: Journal article
Publisher: ASBMB

Abstract english

Subcellular localization of cyclic nucleotide phosphodiesterases (PDEs) may be important in compartmentalization of cAMP/cGMP signaling responses. In 3T3-L1 adipocytes, mouse (M) PDE3B was associated with the endoplasmic reticulum (ER) as indicated by its immunofluorescent colocalization with the ER protein BiP and subcellular fractionation studies. In transfected NIH 3006 or COS-7 cells, recombinant wild-type PDE3A and PDE3B isoforms were both found almost exclusively in the ER. The N-terminal portion of PDE3 can be arbitrarily divided into region 1 (aa 1-300), which contains a large hydrophobic domain with six predicted transmembrane helices, followed by region 2 (aa 301-500) containing a smaller hydrophobic domain (of approximately 50 aa). To investigate the role of regions 1 and 2 in membrane association, we examined the subcellular localization of a series of catalytically active, Flag-tagged N-terminal-truncated human (H) PDE3A and MPDE3B recombinants, as well as a series of fragments from regions 1 and 2 of MPDE3B synthesized as enhanced green fluorescent (EGFP) fusion proteins in COS-7 cells. In COS-7 cells, the localization of a mutant HPDE3A, lacking the first 189 amino acids (aa) and therefore four of the six predicted transmembrane helices (H3A-Delta189), was virtually identical to that of the wild type. M3B-Delta302 (lacking region 1) and H3A-Delta397 (lacking region 1 as well as part of region 2) retained, to different degrees, the ability to associate with membranes, albeit less efficiently than H3A-Delta189. Proteins that lacked both regions 1 and 2, H3A-Delta510 and M3B-Delta604, did not associate with membranes. Consistent with these findings, region 1 EGFP-MPDE3B fusion proteins colocalized with the ER, whereas region 2 EGFP fusion proteins were diffusely distributed. Thus, some portion of the N-terminal hydrophobic domain in region 1 plus a second domain in region 2 are important for efficient membrane association/targeting of PDE3.

Keywords

  • Endocrinology and Diabetes
  • Endoplasmic Reticulum
  • Localization
  • Cyclic Nucleotide Phosphodiesterase
  • Membrane-Association
  • Immunofluorescence

Other

Published
  • Insulin Signal Transduction
  • ISSN: 1083-351X
Eva Degerman
E-mail: eva.degerman [at] med.lu.se

Professor

Insulin Signal Transduction

+46 46 222 85 83

+46 70 885 83 62

BMC C1121b

66

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