Fig. 1. LPR1 is a widely expressed integral membrane protein with a variant lipid phosphate phosphatase catalytic motif. (A) The deduced amino acid sequence of human LPR1 with hydrophobic residues that are predicted to form six transmembrane -helices highlighted in yellow. Residues corresponding to the consensus phosphatase motif found on the LPPs and other family members are highlighted in red. The site of glycosylation is highlighted in purple and the sequence used to generate the LPR1 antibody is boxed. Residues shown in green font were mutated as described in the text. The C-terminus highlighted in green corresponds to the last 43 residues deleted to form the LPR1 C-term 43 mutant described in the text. The consensus phosphatase sequence motif is shown below in alignment with cognate sequences from four proteins of the LPR family. Residues that participate in the charge relay catalytic mechanism of the phosphatase reaction are highlighted in red and residues that contact the substrate or transition state phosphate group are highlighted in blue. Residues within this motif that are divergent in LPR1 and related proteins are underlined. (B) Membrane protein preparations from insect cells expressing LPP1 or LPR1 were analyzed by western blotting using an LPR1-specific antibody. Asterisk denotes an LPR1-specific immunoreactive band of 35-38 kDa. Samples contained equal quantities of proteins. (C) LPR1 expression in mouse tissues was analyzed by western blotting. Samples contained equal quantities of protein.