Fig. 2

A balanced expansion of inhibitory and activating receptors occurred in bat species. Amino acid sequences of transmembrane and cytoplasmic domains of the CEA-related CEACAMs in M. lucifugus were aligned using ClustalW. a Sequences derived from inhibitory receptors. Amino acids which differ from the CEACAM1-like consensus sequence were marked in red. The immunoreceptor tyrosine-based inhibition motif (ITIM) and immunoreceptor tyrosine-based switch motif (ITSM) are highlighted in yellow and green, respectively. b Amino acid sequences from CEACAMs having an immunoreceptor tyrosine-based activation motif (ITAM) motif in the cytoplasmic tail. Amino acids which differ from the CEACAM3-like consensus sequence were marked in red. ITAM motifs are highlighted in blue. a and b Sequences marked with asterisks are derived from genes which have mutated splice donor sites between cytoplasmic exons. c The number of transmembrane domains associated with ITIM and ITAM signaling motifs of all bat species analyzed are depicted. Cyt, cytoplasmic; TM, transmembrane