The heat shock proteins (HSPs) comprise a group of highly conserved, abundantly expressed proteins with diverse functions, including the assembly and sequestering of multi-protein complexes, the transportation of nascent poly-peptide chains across cellular membranes and the regulation of protein folding. The gene is located in the major histocompatibility complex class III region, in a cluster with two closely related genes which also encode isoforms of the 70kDa heat shock protein. HSPA1L (heat shock 70 kDa protein 1L), also known as HSP70T, is a 641 amino acid protein that belongs to the HSP 70 family and, like other HSP proteins, mediates protein folding within the cytosol, as well as within other organelles throughout the cell. HSP proteins, such as HSPA1L, together with chaperones, bind extended peptide segments with a net hydrophobic character exposed during protein translation, membrane translocation or after stress-induced damage. HSPA1L has been found be expressed in spermatids and is not induced by heat shock.