The N-LIP and C-LIP domains are boxed. The conserved DxDxT domain is shown in bold. B) A schematic representation of TbLpn amino acid sequence aligned with members of the lipin

family is shown in the left panel. The degree of amino acid sequence identity between TbLpn and members of the lipin family is shown on the right panel. TbLpn [T. brucei, (Tb), accession number AAX78871], Lipin-1 [Human, (Hs), AAH30537], Lipin-2 [Human, (Hs), AAI52449], Lipin-3 [Human (Hs), CAI42978], Lipin-1 [Mouse, (Mm), NP_766538], Lipin-2 [Mouse (Mm), AAH39698], Lipin-3 [Mouse (Mm), EDL06298], Lipin-M [Drosophila melanogaster, AZD3965 purchase (Dm), NP_001188884], Lipin-1 [Danio rerio, (Dr), AAX19945], Smp2 [Saccharomyces cerevisiae, (Sc), BAA00880]. Inhibitor Library nmr To begin to characterize TbLpn, we amplified the complete predicted ORF from PF cDNA. Sequence analysis revealed six nucleotide differences from the Tb927.7.5450 sequence reported in GeneDB, three of which result in amino acid changes (Glu-157 → Gly-157, Lys-675 → Thr-675, Val-715 → Ala-715). The predicted TbLpn protein is 806 amino acids in length (Figure 1A) with a predicted molecular mass of 86.7 kDa. The N-LIP domain of TbLpn displays 30–37.5% amino acid identity with the corresponding domains from lipin proteins (Figure 1B and Figure 2A). In addition,

the C-LIP domain of TbLpn exhibits 46-50% amino acid identity with the corresponding domains from members of lipin family, such as mammalian lipin-1, lipin-2, lipin-3, and yeast Smp2 (Figure 1B and Figure 2B). Most interesting, the motif (DXDXT) shown to confer phosphatidic acid phosphatase activity to mammalian and yeast lipins, is present within the C-LIP domain of TbLpn (445DVDGT) [43]. In addition, a conserved glycine residue shown to be essential for

the mouse Lipin-1 function is also present in the predicted amino acid sequence of TbLpn (Gly-74) [39]. Apart from this domain, no significant homology is observed between TbLpn and other members of the Silibinin lipin family. For instance, although lipin proteins share the LXXIL motif, which has been shown to be essential for interaction of Lipin-1 with the nuclear cofactors involved in the regulation of fatty acid metabolism, TbLpn lacks that conserved LXXIL motif, suggesting that TbLpn might have a different function than other lipins [48]. Although TbLpn may not possess co-transcriptional activity, it might still act as a phosphatidic acid phosphatase. In addition, the conserved nuclear localization sequence, usually found in almost all species [34], is absent in TbLpn. Figure 2 Amino acid sequence alignment of TbLpn conserved domains and other lipin family members. A) Amino acid sequence alignment of N-LIP domains. Sequences were aligned using CLUSTALW. Identical and conserved amino acids are shown in black and grey boxes, respectively. B) Amino acid sequence alignment of C-LIP domains. Sequences were aligned using CLUSTALW.