Signaling Threshold Regulating Transmembrane Adaptor 1 (SIT1)

Sequence analysis predicted that SIT has a putative 22-amino acid hydrophobic leader peptide, an 18-amino acid extracellular domain containing a potential N-glycosylation site and a cys residue that may be involved in an interchain disulfide bond, a 20-amino acid transmembrane domain, and a 136-amino acid intracellular portion containing several potential phosphorylation sites.

SIT also contains 6 tyrosine residues, 5 of which may be involved in Src homology-2 (SH2) domain-mediated protein-protein interactions after phosphorylation. The cytoplasmic portion of SIT possesses a potential immunoreceptor tyrosine-based inhibitory motif, or ITIM, suggesting the potential for interactions with SHP1 (PTPN6) or SHP2 (PTPN11).