From a human fetal-brain cDNA library we isolated a novel cDNA clone encoding a protein containing a CAP-GLY domain that is highly conserved among several cytoskeleton-associated proteins. The CAP-GLY domain is thought to be essential for their association with microtubules. The cDNA, designated CKAPI (for cytoskeleton-associated protein I, glycine motif) contained an open reading frame of 579 nucleotides encoding 193 amino acids. Northern-blot analysis revealed expression of three transcripts, 1.0, 3.4, and 4.6 kb in size, in all tissues examined. The 1.0-kb transcript was significantly higher in brain and heart than in other tissues. This gene was mapped by FISH to chromosome bands 19q13.11-->q13.12.