Pex15p of Saccharomyces cerevisiae provides a molecular basis for recruitment of the AAA peroxin Pex6p to peroxisomal membranes.
The gene products (peroxins) of at least 29 PEX genes are known to be necessary for peroxisome biogenesis but for most of them their precise function remains to be established. Here we show that Pex15p, an integral peroxisomal membrane protein, in vivo and in vitro binds the AAA peroxin Pex6p. This interaction functionally interconnects these two hitherto unrelated peroxins. Pex15p provides the mechanistic basis for the reversible targeting of Pex6p to peroxisomal membranes. We could demonstrate that the N-terminal part of Pex6p contains the binding site for Pex15p and that the two AAA cassettes D1 and D2 of Pex6p have opposite effects on this interaction. A point mutation in the Walker A motif of D1 (K489A) decreased the binding of Pex6p to Pex15p indicating that the interaction of Pex6p with Pex15p required binding of ATP. Mutations in Walker A (K778A) and B (D831Q) motifs of D2 abolished growth on oleate and led to a considerable larger fraction of peroxisome bound Pex6p. The nature of these mutations suggested that ATP-hydrolysis is required to disconnect Pex6p from Pex15p. On the basis of these results, we propose that Pex6p exerts at least part of its function by an ATP-dependent cycle of recruitment and release to and from Pex15p.
Birschmann
Ingvild
I
Abteilung für Zellbiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Germany.
Stroobants
An K
AK
van den Berg
Marlene
M
Schäfer
Antje
A
Rosenkranz
Katja
K
Kunau
Wolf-H
WH
Tabak
Henk F
HF
D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008854:Microscopy, Electron; D020675:Peroxisomes / Q000378:metabolism* / Q000648:ultrastructure; D010750:Phosphoproteins / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins
D008565:Membrane Proteins; C110177:PEX15 protein, S cerevisiae; D010750:Phosphoproteins; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C490760:PEX6 protein, S cerevisiae; C096998:Pex6 protein, rat