Hand and Reconstructive Surgery, Medical School Hannover, Podbielskistraße 380, D-30659 Hannover, Germany,

E-mail: [email protected]

Th e Bax Inhibitor-1 (BI-1) family is an evolutionarily conserved protein family of small hydrophobic proteins. Experimental observations and comparative studies suggest that each of the family members has six to seven transmembrane regions and localizes in diff erent cellular membranes. Published data indicate that, although most members of this family are still not characterized with regard to their functional mechanisms, a cytoprotective eff ect has been connected to BI-1, Lifeguard (LFG), Glutamate receptor, Ionotropic, N-methyl-D-aspartate Associated Protein (GRINA), Responsive to centrifugal force and shear stress gene (RECS) 1, Growth hormone-inducible transmembrane protein (Ghitm) and the Golgi anti-apoptotic protein (GAAP) expression. Th is cytoprotection includes an inhibition of various apoptotic stimuli like inducers of endoplasmic reticulum (ER) stress (BI-1), Fas death receptor stimulation (LFG), inducers of mitochondrial apoptosis (Ghtim and h-GAAP). A central element of cytoprotection is control of ion homeostasis and intracellular calcium fl uxes, which infl uence sensitivity against ER stress phenomena. In their variability the members of the BI-1 family

are an interesting example for the high number of regulatory strategies that cells implicate on their apoptotic pathways. Th is makes the protein family an interesting target for therapeutical uses like the development of new drugs and gene therapeutic approaches for all kinds of diseases with pathogenes is based on cellular stress responses and apoptotic dysregulations.