The TCP1 ring complex (TRiC) is a molecular chaperone involved in actin and tubulin folding. Little is known about the components of this complex. The first component identified was TCP1, a protein coded by a gene in the t-complex locus on mouse chromosome 17. This locus is involved in several embryonic defects, male sterility, and the transmission ratio distortion. In humans, the t-complex genes map to chromosome 6. Other components of TRiC are thought to be TCP1-related proteins. Recently, a mouse cDNA coding for one of these proteins has been cloned and named mTRiC-P5. Here we report the cloning of a partial human cDNA clone, homologous to mTRiC-P5, and its chromosome localization by fluorescence in situ hybridization. The human TRiC-P5 gene (TRIC5) maps to human chromosome 1q23, a region known to be a preferential chromosomal breakpoint involved in leukemia. Therefore, even if TCP1 and TRiC-P5 are related proteins and are found in the same protein complex, they are not coded by syntenic genes in humans.