Domain mapping on the human metastasis regulator protein h-Prune reveals a C-terminal dimerization domain

Sabine Middelhaufe , Livia Garzia , Uta-Maria Ohndorf , Barbara Kachholz , Massimo Zollo , Clemens Steegborn (1)

1 Department of Physiological Chemistry [Bochum]

The human ortholog of the drosophila prune protein (h-Prune) is an interaction partner and regulator of the metastasis suppressor protein NM23-H1. Studies on a cellular breast cancer model showed that inhibition of the cAMP-specific phosphodiesterase activity of h-Prune can lower the incidence of metastasis formation, suggesting h-Prune inhibition as an exciting approach for therapy of metastatic tumors. H-Prune shows no sequence similarity to known mammalian phosphodiesterases, but instead appears to belong to the DHH (Asp-His-His) superfamily of phosphoesterases. In order to investigate the structure and molecular function of h-Prune, we established its recombinant expression in a bacterial system. Through sequence analysis and limited proteolysis, we could identify domain boundaries and a potential coiled-coil region in a C-terminal cortexillin homology domain. We found that this C-terminal domain mediates h-Prune homodimerization as well as its interaction with NM23-H1. The phosphodiesterase catalytic domain of h-Prune was mapped to the N-terminus and shown to be active even in a monomeric form. Our findings indicate an architecture of h-Prune with two independent active sites and two interaction sites for the assembly of oligomeric signaling complexes.

Mots clés: Life Sciences

Sabine Middelhaufe, Livia Garzia, Uta-Maria Ohndorf, Barbara Kachholz, Massimo Zollo, et al.. Domain mapping on the human metastasis regulator protein h-Prune reveals a C-terminal dimerization domain. Biochemical Journal, 2007, 407 (2), pp.199-205. ⟨10.1042/BJ20070408⟩. ⟨hal-00478779⟩