Journal article

The structure of the PA28-20S proteasome complex from Plasmodium falciparum and implications for proteostasis

Stanley C Xie, Riley D Metcalfe, Eric Hanssen, Tuo Yang, David L Gillett, Andrew P Leis, Craig J Morton, Michael J Kuiper, Michael W Parker, Natalie J Spillman, Wilson Wong, Christopher Tsu, Lawrence R Dick, Michael DW Griffin, Leann Tilley



The activity of the proteasome 20S catalytic core is regulated by protein complexes that bind to one or both ends. The PA28 regulator stimulates 20S proteasome peptidase activity in vitro, but its role in vivo remains unclear. Here, we show that genetic deletion of the PA28 regulator from Plasmodium falciparum (Pf) renders malaria parasites more sensitive to the antimalarial drug dihydroartemisinin, indicating that PA28 may play a role in protection against proteotoxic stress. The crystal structure of PfPA28 reveals a bell-shaped molecule with an inner pore that has a strong segregation of charges. Small-angle X-ray scattering shows that disordered loops, which are not resolved in the crysta..

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Awarded by National Health and Medical Research Council of Australia

Awarded by Global Health Innovation Technology Fund

Awarded by Australian Research Council

Funding Acknowledgements

We thank S. Tiash, The University of Melbourne, for technical support and advice and J. R. Beck, Iowa State University, for assistance with the generation of the pAIO-DHFR-PA28 vector. This work was supported by the National Health and Medical Research Council of Australia (grant nos. APP1092808, APP1072217) and the Global Health Innovation Technology Fund (grant no. GHIT T2015-134). M.D.W.G. is the recipient of an Australian Research Council Future Fellowship (project no. FT140100544). M.W.P. is a National Health and Medical Research Council of Australia Research Fellow (no. APP1117183). Funding from the Victorian Government Operational Infrastructure Support Scheme to St Vincent's Institute is acknowledged. We thank the Medicines for Malaria Venture for ongoing support and the Australian Red Cross Blood Bank for the provision of human red blood cells and serum. We thank the Australian Synchrotron, part of the Australian Nuclear Science and Technology Organisation, for the provision of beamtime, and the beamline staff at the SAXS/WAXS and MX2 beamlines. This work made use of the ACRF Detector at the MX2 beamline. Initial crystallization screens were conducted at the CSIRO Collaborative Crystallisation Centre ( We thank the Bio21 Institute Advanced Microscopy Facility at The University of Melbourne.