Pex19p-dependent Targeting of Pex17p, a Peripheral Component of the Peroxisomal Protein Import Machinery

• Published in: The Journal of biological chemistry 2006-07, Vol.281 (28), p.19417-19425
• Main Authors: Girzalsky, Wolfgang, Hoffmann, Linda S., Schemenewitz, Andreas, Nolte, Andreas, Kunau, Wolf-Hubert, Erdmann, Ralf
• Format: Article
• Language: English
• Subjects: Base Sequence; Binding Sites; Carrier Proteins - metabolism; Cell Membrane - metabolism; Cytosol - metabolism; Membrane Proteins - metabolism; Membrane Transport Proteins; Molecular Sequence Data; Peroxins; Peroxisomes - chemistry; Protein Transport; Repressor Proteins - metabolism; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - metabolism; Signal Transduction; Two-Hybrid System Techniques
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M603344200

Pex19p is required for the topogenesis of peroxisomal membrane proteins (PMPs). Here we have demonstrated that Pex19p is also required for the peroxisomal targeting and stability of Pex17p, a peripheral component of the docking complex of the peroxisomal protein import machinery. We have demonstrated that Pex17p is associated with the peroxisomal Pex13p-Pex14p complex as well as with Pex19p. We have identified the corresponding binding sites for Pex14p and Pex19p and demonstrated that a specific loss of the Pex19p interaction resulted in mistargeting of Pex17p. We have shown that a construct consisting only of the Pex19p- and Pex14p-binding sites of Pex17p is sufficient to direct an otherwise cytosolic reporter protein to the peroxisomal membrane in a Pex19p-dependent manner. Our data show that the function of Pex19p as chaperone or import receptor is not restricted to integral membrane proteins but may also include peripheral PMPs. As a consequence of our data, the previous definition of a targeting signal for PMPs (mPTS) as a Pex19p-binding motif in conjunction with a transmembrane segment should be extended to regions comprising a Pex19p-binding motif and a peroxisomal anchor sequence.