This family consists of several fas apoptotic inhibitory molecule (FAIM1) proteins. FAIM expression is upregulated in B cells by anti-Ig treatment that induces Fas-resistance, and overexpression of FAIM diminishes sensitivity to Fas-mediated apoptosis of B and non-B cell lines. FAIM1 is highly evolutionarily conserved and is widely expressed in murine tissues, suggesting that FAIM plays an important role in cellular physiology [1].

1: An alternatively spliced long form of Fas apoptosis inhibitory molecule (FAIM) with tissue-specific expression in the brain. Zhong X, Schneider TJ, Cabral DS, Donohoe TJ, Rothstein TL; Mol Immunol 2001;38:65-72. PMID:11483211