Amino acid sequences of mammalian PSGL-1. (A) Multiple alignment of 12 complete PSGL-1 amino acid sequences and (B) of N-terminal sequences from putative PSGL-1 proteins of cat and sheep, which were inferred respectively from partial genomic sequence and EST sequences identified through homology searches (EMBL/Genbank/DDBJ respective accession numbers: AANG01098304 and DY506895). The putative signal peptide (SP) and propeptide (Pro) cleavage sites are indicated by arrows. The consensus sequence for propeptide cleavage (RX [R/K]R), recognized by PACE, is boxed. Threonine homologous to human Thr-57 is indicated by a black arrowhead. Arbitrary gaps have been added in each sequence in order to isolate and align separately the mucin-like region containing the decameric repeats, which is surrounded by a frame. The transmembrane domain (TM) is marked by a bar. Asterisks indicate the amino acids involved in moesin binding.