Figure 1.

Primary sequence and processing of AtSPP. A, Alignment of the predicted primary sequence of AtSPP (At2g03120) with human SPP (HsSPP). Identical residues are highlighted in dark gray, and similar residues are highlighted in light gray. The conserved active site Asp residues are marked with asterisks, and the conserved QPALLY sequence is underlined. The black arrowhead indicates the point of disruption of the primary sequence by the T-DNA insertion in the spp-2 mutant. B, Comparison of in vivo expressed and in vitro translated AtSPP-Flag. Protein extracted from AtSPP-Flag transgenic plants (lane 1) or translated in an in vitro reticulocyte lysate (lane 2) was resolved by SDS-PAGE and immunoblotted with anti-Flag antibody. Protein extract from untransformed plants was used as a negative control (lane 3).