Murine Gas2 is a microfilament-associated protein whose expression is increased at growth arrest in mammalian cells. During apoptosis, Gas2 is specifically cleaved at its C-terminus by a still unknown ICE-like protease, and the processed protein induces dramatic rearrangements in the cytoskeleton when overexpressed in several cell types. Here we report the characterization of a cDNA encoding the human homologue of Gas2, showing high conservation with the murine counterpart at the protein level. Fluorescence in situ hybridization analysis and radiation hybrid mapping localized the GAS2 gene on human chromosome 11p14.3-p15.2, in a region homologous to the gas2 region on mouse chromosome 7.