title: Pex19p-dependent targeting of Pex17p, a peripheral component of the peroxisomal protein import machinery.
abstract: 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.
authors: Abteilung für Systembiochemie, Institut für Physiologische Chemie, Ruhr-Universität Bochum, D-44780 Bochum, Germany.
authors: Wolfgang
authors: W
authors: Girzalsky
authors: Linda S
authors: LS
authors: Hoffmann
authors: Andreas
authors: A
authors: Schemenewitz
authors: Andreas
authors: A
authors: Nolte
authors: Wolf-Hubert
authors: WH
authors: Kunau
authors: Ralf
authors: R
authors: Erdmann