Programmed cell death: death for life

Programmed cell death (apoptosis) is necessary for the normal development and existence of multicellular organisms. Apoptosis is used to remove cells whose survival is undesirable for the organism. One of the receptors that initiate apoptosis is the protein CD95 (Fas), which is expressed on the membrane of various cell types and is involved in the transmission of cytotoxic signals. In addition to membrane proteins, soluble forms of the protein resulting from alternative splicing have been described. Among them, a dominant and a minor variant are distinguished, which exhibit different functional features. The functional properties of the soluble forms of Fas protein are also determined by their structural organization. Monomeric variants of the molecule inhibit apoptosis, while oligomeric forms exhibit cytotoxic properties. This book provides insight into the expression pattern of membrane-dominant and minor soluble forms of Fas in different human cell types and the mechanisms of their possible involvement in the regulation of apoptosis. Changes in the number, composition and expression level of Fas mRNA in cells in comparison with the serum concentration of the protein in norm and diseases characterized by different degrees of apoptotic processes are described.