Stannin (SNN)

Stannin (SNN) is an 88-amino acid, highly conserved monotopic membrane protein localized primarily to mitochondria and vesicular organelles. Stannin contains a single transmembrane helix, an unstructured cytoplasmic linker domain with a conserved CXC metal-binding motif and putative binding site for 14-3-3-zeta, and a distorted cytoplasmic helix. Stannin is essential for mediating apoptosis and growth arrest initiated by environmental organotin compounds such as trimethyltin. It acts as a molecular sensor and mediator of mitochondrial damage, triggers signaling processes such as p38-ERK activation and p53-dependent pathways, and is involved in cross-talk between mitochondrial and nuclear compartments. Its expression is regulated by cellular stress signals, including TNF-alpha in endothelial cells. Stannin knockdown impairs cell cycle progression and growth, highlighting its role in normal and stress-induced cellular processes.

Other names

StanninSNNAG8_1Hemotin

Binding of organotin compounds (e.g., trimethyltin) at the CXC motif initiates conformational changes that recruit signaling partners (14-3-3-zeta), starting the apoptotic cascade. Regulation of cell cycle via p53-, PKC-epsilon-, and p38-ERK signaling pathways in response to stimuli such as TNF-alpha.