Figure 2.

Binding between NaAsO₂ and the RING finger domains of RNF20 and RNF40 in cells. (a) Streptavidin agarose affinity pull-down assay using biotin-As as a probe revealed the binding of As(III) with RNF20 or RNF40 in cells. Pretreatment of cells with 10 μM NaAsO₂ or PAPAO for 1 h attenuated the binding, and mutations of RING finger cysteines to alanines abrogated the pull-down of RNF20 and RNF40 with the biotin-As probe. (b) Colocalization of As(III)-bearing ReAsH with GFP-RNF20 and GFP-RNF40 in HEK293T cells, and such colocalization is lost in cells pretreated with 10 μM NaAsO₂ or PAPAO, but not Zn²⁺. (c) Mutations of RING finger cysteines to alanines abolished the colocalization of RNF20 or RNF40 with ReAsH.