Fig. 1. Comparison of properties of the two families of centrin-binding proteins PtCenBP2/3 and PtCenBP1. (A) Alignment of the primary structures of PtCenBP1p and PtCenBP2/3p shows their regions of homology. R1-R6 correspond to the six identical repeats of 427 amino acids present in PtCenBP1 (Gogendeau et al., 2007). The proteins are highly similar throughout their length, except for the absence of the central repetitions in PtCenBP2/3p. (B) PtCenBP3p displays numerous potential centrin-binding sites that are similar to the centrin-binding consensus defined by Kilmartin (Kilmartin, 2003). The Weblogos of the 30 centrin-binding sites present in PtCenBP3 are compared with those corresponding to the sites present in the human Sfi1p and in PtCenBP1p (Gogendeau et al., 2007). (C) Wild-type cells expressing either GFP-PtCenBP3p (right) or GFP-PtCenBP1p (left) were double-labelled with anti-GFP antibodies (green) and the anti-centrin 1A9 antibody (red). In the GFP-PtCenBP3p expressing cells, the two labels do not colocalise, whereas in the GFP-PtCenBP1p-expressing cells, the two labels colocalise across the network. (D) Wild-type cells were submitted to RNAi targeted either to PtCENBP3 (right) or PtCENBP1 (left) and the organisation of the ICL monitored with the anti-centrin antibody 1A9. A collapse of the ICL is observed in a PtCENBP3-silenced cell after 48 hours. By contrast, in PtCENBP1-silenced cells (after 48 hours of feeding), the ICL is totally disassembled, leaving only small remnants that flank basal bodies. Scale bars: 15 µm.