8u0v
S. cerevisiae Pex1/Pex6 with 1 mM ATP
Structural highlights
FunctionPEX1_YEAST Component of the PEX1-PEX6 AAA ATPase complex, a protein dislocase complex that mediates the ATP-dependent extraction of the PEX5 receptor from peroxisomal membranes, an essential step for PEX5 recycling (PubMed:15634331, PubMed:16007078, PubMed:16911527, PubMed:26170309, PubMed:26066397, PubMed:29321502). Specifically recognizes PEX5 monoubiquitinated at 'Cys-6', and pulls it out of the peroxisome lumen through the PEX2-PEX10-PEX12 retrotranslocation channel (PubMed:26170309, PubMed:26066397, PubMed:29321502). Extraction by the PEX1-PEX6 AAA ATPase complex is accompanied by unfolding of the TPR repeats and release of bound cargo from PEX5 (PubMed:29321502).[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedThe heterohexameric AAA-ATPase Pex1/Pex6 is essential for the formation and maintenance of peroxisomes. Pex1/Pex6, similar to other AAA-ATPases, uses the energy from ATP hydrolysis to mechanically thread substrate proteins through its central pore, thereby unfolding them. In related AAA-ATPase motors, substrates are recruited through binding to the motor's N-terminal domains or N-terminally bound co-factors. Here we use structural and biochemical techniques to characterize the function of the N1 domain in Pex6 from budding yeast, S. cerevisiae. We found that although Pex1/DeltaN1-Pex6 is an active ATPase in vitro, it does not support Pex1/Pex6 function at the peroxisome in vivo. An X-ray crystal structure of the isolated Pex6 N1 domain shows that the Pex6 N1 domain shares the same fold as the N terminal domains of PEX1, CDC48, and NSF, despite poor sequence conservation. Integrating this structure with a cryo-EM reconstruction of Pex1/Pex6, AlphaFold2 predictions, and biochemical assays shows that Pex6 N1 mediates binding to both the peroxisomal membrane tether Pex15 and an extended loop from the D2 ATPase domain of Pex1 that influences Pex1/Pex6 heterohexamer stability. Given the direct interactions with both Pex15 and the D2 ATPase domains, the Pex6 N1 domain is poised to coordinate binding of co-factors and substrates with Pex1/Pex6 ATPase activity. The N1 domain of the peroxisomal AAA-ATPase Pex6 is required for Pex15 binding and proper assembly with Pex1.,Ali BA, Judy RM, Chowdhury S, Jacobsen NK, Castanzo DT, Carr KL, Richardson CD, Lander GC, Martin A, Gardner BM J Biol Chem. 2023 Nov 28:105504. doi: 10.1016/j.jbc.2023.105504. PMID:38036174[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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