Figure 1

Cartoon representation of LPCAT1 (A) and alignment of Motif III residues of some LPLAT members (B). (A) Motifs I, II, III and IV of LPCAT1 enzyme (GenBank accession number: NP_663351), conserved among LPLAT enzymes, are indicated in light grey. Four predicted transmembrane spanning segments (TM1, TM2, TM3, TM4) [16] are shown in black. The topology of LPCAT1 is not know and the presented model is only representative of a prediction that would support orientation of all 4 conserved motifs to the cytosolic side (or near the cytosolic membrane surface) with exposure of the two predicted EF-hand motifs on the cell surface. The amino acid sequence of the EFh-1 motif, with the 6 most conserved residues underlined, is shown. The 12 cysteines are also indicated. (B) Amino acid alignment of motif III of members of the mouse Agpat and Lpcat families. The arginine and a cysteine residue found at the + 1 position of the PEGT motif are indicated. When known, enzymatic activity of the protein is indicated on the right. Substrate specificity of Agpat4 and Agpat5 is not known but the two members are predicted to be LPAAT enzyme. Agpat7 is now annotated as Lpcat4. The acyl-CoA:lysoCardiolipin acyltransferase 1 protein (ALCAT1) [42], currently annotated as LCLAT1, was mis-identified by Agarwal et al. [43] as a new member of the AGPAT family, AGPAT8. The annotation for Agpat8 has been removed from database. Not shown is LPCAT3, formerly annotated as membrane-bound O-acyltransferase 5 (Mboat5), which differs from other LPCAT members [44, 45].