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  • The EMBO Journal (1997) 16, 44 - 53
  • doi:10.1093/emboj/16.1.44

The Hansenula polymorpha PEX14 gene encodes a novel peroxisomal membrane protein essential for peroxisome biogenesis

Masayuki Komori1, Søren W. Rasmussen2, Jan A.K.W. Kiel1, Richard J.S. Baerends1, James M. Cregg3, Ida J. van der Klei1 and Marten Veenhuis1

  1. Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), Biological Centre, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands
  2. Carlsberg Laboratory, Department of Physiology, Gamle Carlsberg Vej 10, DK–2500 Valby, Copenhagen, Denmark
  3. Department of Chemistry, Biochemistry, and Molecular Biology, Oregon Graduate Institute of Science and Technology, Portland, OR 97291-1000, USA

Correspondence to:

Marten Veenhuis,

Received 21 May 1996; Revised 18 September 1996

We have cloned the Hansenula polymorpha PEX14 gene by functional complementation of the chemically induced pex14-1 mutant, which lacked normal peroxisomes. The sequence of the PEX14 gene predicts a novel protein product (Pex14p) of 39 kDa which showed no similarity to any known protein and lacked either of the two known peroxisomal targeting signals. Biochemical and electron microscopical analysis indicated that Pex14p is a component of the peroxisomal membrane. The synthesis of Pex14p is induced by peroxisome-inducing growth conditions. In cells of both pex14-1 and a PEX14 disruption mutant, peroxisomal membrane remnants were evident; these contained the H.polymorpha peroxisomal membrane protein Pex3p together with a small amount of the major peroxisomal matrix proteins alcohol oxidase, catalase and dihydroxyacetone synthase, the bulk of which resided in the cytosol. Unexpectedly, overproduction of Pex14p in wild-type H.polymorpha cells resulted in a peroxisome-deficient phenotype typified by the presence of numerous small vesicles which lacked matrix proteins; these were localized in the cytosol. Apparently, the stoichiometry of Pex14p relative to one or more other components of the peroxisome biogenesis machinery appears to be critical for protein import.

  • Keywords:

    • Hansenula polymorpha,
    • peroxisome,
    • peroxisome deficiency,
    • PEX14 gene