Pex15p of Saccharomyces cerevisiae provides a molecular basis for recruitment of the AAA peroxin Pex6p to peroxisomal membranes
Pex15p of Saccharomyces cerevisiae provides a molecular basis for recruitment of the AAA peroxin Pex6p to peroxisomal membranes
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DOI：
10.1091/mbc.e02-11-0752
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发表时间：
2003-06-01
影响因子：
3.3
通讯作者：
Tabak, HF
中科院分区：
文献类型：
--
作者：
Birschmann, I;Stroobants, AK;Tabak, HF
已知至少29个PEX基因的基因产物(过氧化物素)是过氧化酶体生物发生所必需的，但对其中大多数基因而言，其确切功能仍有待确定。在这里，我们证明了Pex15p，一个完整的过氧体膜蛋白，在体内和体外与AAA Peroxin Pex6p结合。这种相互作用在功能上将这两种迄今不相关的过氧化物素联系在一起。Pex15p为Pex6p可逆靶向过氧化物体膜提供了机制基础。我们可以证明Pex6p的N-末端含有Pex15p的结合位点，并且Pex6p的两个AAA盒D1和D2对这种相互作用具有相反的作用。D1Walker A基序(K489A)的点突变降低了Pex6p与Pex15p的结合，表明Pex6p与Pex15p的相互作用需要结合ATP。Walker A(K778A)和B(D831Q)的突变：D2的基序阻止了油酸的生长，并导致了相当大比例的过氧化物体，结合了Pex6p。这些突变的性质表明，需要ATP水解酶才能将Pex6p与Pex15p断开。在这些结果的基础上，我们认为Pex6p至少通过一个依赖于ATP的Pex15p募集和释放循环发挥其部分功能。
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.