Pex13p: docking or cargo handling protein?
The Src homology 3 (SH3) domain-containing peroxisomal membrane protein Pex13p is an essential component of the import machinery for matrix proteins and forms a binding site for the peroxisomal targeting type I (PTS1) receptor Pex5p. The interaction between these two proteins can be described as novel in several ways. In the yeasts Saccharomyces cerevisiae and Pichia pastoris, the SH3 domain itself is responsible for the interaction but not via the typical P-x-x-P motifs that are common to SH3 ligands as Pex5p lacks such a motif. Instead, a region of Pex5p containing a W-x-x-x-F/Y motif is crucial for this binding. In mammals, again W-x-x-x-F/Y motifs appear to be important for the interaction but the SH3 domain seems not to be the site for Pex5p binding, this being located in the N-terminus of Pex13p. Despite these differences in the details of the Pex13p-Pex5p interaction, the association of the two proteins is a crucial step in Pex5p-mediated protein import into peroxisomes in both yeasts and mammals.
Williams
Chris
C
Department of Medical Biochemistry, Academic Medical Center, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
Distel
Ben
B
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D008322:Mammals; D008565:Membrane Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D000074435:Peroxisome-Targeting Signal 1 Receptor; D010843:Pichia / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D018909:src Homology Domains
D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C491105:PEX13 protein, S cerevisiae; C499509:PEX5 protein, S cerevisiae; D000074435:Peroxisome-Targeting Signal 1 Receptor; D029701:Saccharomyces cerevisiae Proteins