The human protein SPAG1 is an essential protein factor for the correct assembly of dynein complexes. These complexes are required for the activity of cellular cilia that are responsible of cellular mobility functions. However, no structural study of SPAG1 had been undertaken to date.

Thanks to the B2S core facility, researchers from IMoPA (UMR 7365 CNRS-UL), LCPT (UMR 7019 CNRS-UL) and IBSLor (UMS 2008 CNRS-UL-INSERM) laboratories have analyzed the close link between SPAG1 and the HSP70 and HSP90 chaperones at the atomic level. They showed that SPAG1 was made of 3 TPR domains. The resolution of the 3D structure of one of these domains has revealed how HSP70 and HSP90 are recruited by SPAG1.

Finally, this study questions the direct nucleotidase activity of SPAG1. The authors propose a regulatory role of the protein on the ATPases/GTPase functions of chaperones.

Publication: Chagot ME, Dos Santos Morais R, Dermouche S, Lefebvre D, Manival X, Chipot C, Dehez F, Quinternet M. Binding properties of the quaternary assembly protein SPAG1. Biochem J. 2019 May 22.

DOI: 10.1042/bcj20190198

PMID: 31118266

HAL: HAL-02140524