Fig. 1. (a) One-letter amino acid sequence of PAT1. The region of PAT1 predicted to form a coiled-coil is shown in the shaded box, and the four imperfect KLC-like tandem repeats are in the open boxes. Putative protein kinase C phosphorylation sites are denoted by . (b) Alignment of the KLC-like repeats. The four 42-amino acid, imperfect KLC-like tandem repeats in PAT1 aligned with KLC repeats from various organisms. The numbers indicate the position of amino acids in PAT1 sequence. C-KLC , Caenorhabditis elegans (accession no. P46822); s-KLC, squid (accession no. P46825); D-KLC, Drosophila (accession no. P46824); ch-KLC, chicken (accession no. 1208772); h-KLC, human (accession no. Q07866). An appendix with information on sequence analysis, alignments, etc., is published as supplemental data on the PNAS web site (www.pnas.org).