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. 2016 Sep 8;99(4):886–893. doi: 10.1016/j.ajhg.2016.07.011

Figure 2.

Figure 2

Alignment and Molecular Modeling of the Impact of p.Cys1691Ser Variant on the GPS Motif

(A) Schematic representation of the human PKD1L1 structural domains. PKD1L1 has two Ig-like PKD domains, a REJ domain and a GPS motif in the N-terminal extracellular region, an LH2/Plat domain in the first intracellular loop, and a coiled-coil domain at the C-terminal (CC).

(B and C) 3D models of the GPS motif in PDK1L1 in the wild-type (B) and p.Cys1691Ser mutant (C) by Phyre2 based on the GPS motif in the GAIN and HormR domains of human brain angiogenesis inhibitor 3 (BAI3). The five β strands are shown with numbered amino acids corresponding to the coding sequence of PKD1L1. Cys to Ser substitution at the position 1691 (magnification boxed in red) eliminates the highly conserved disulfide bridge between cysteine residues 1691 and 1717 represented by the yellow solid bar. The conserved Leu1722 residue at the putative cleavage site is boxed in blue.

(D) Alignment of the GPS motif in PKD1L1, other members of PC-1 family, and G protein couple receptors (GPCRs). The GPS motif contains four conserved cysteines arranged in a specific fashion (C-x2-W-x6-16- W-x4-C-x-10-22-C-x-C) just before the first transmembrane domain. The conserved cysteine (C) residues are boxed; the conserved tryptophan (W) residues are highlighted in magenta. The first cysteine residues are numbered with respect to the protein sequence. PKD1L1 and PKD1 do not have the second and fourth (II and IV) cysteine residues in the conserved positions. The putative cleavage site leucine residues that are located in the turn between the last two β strands of the GPS motif are highlighted in green in the alignment. Highlighted in cyan is the mutant site of PKD1L1 GPS in subject 3 (II-1 from family 2) of this study. Highlighted in red are the previously reported mutant sites in the GPS motif in hPKD1, hBAI3, and hGPR56 and cLAT-1. Abbreviations are as follows: h, human; r, rat; m, mouse; c, C. elegans.

(E) ClustalW multiple alignment analysis shows high level evolutionary conservation of the human Cys1691 residue in PKD1L1 across multiple species (highlighted in gray).