Heat Shock 40kDa Protein 3 (HSPF3)

The cDNA lacking the insert encodes a deduced protein of 277 amino acids, whereas the cDNA containing the insert has an alternative C-terminal sequence that is 74 amino acids longer. The similarity between the HSJ1 and DnaJ proteins is restricted to the N-terminal region. In addition, the N-terminal and central regions of the HSJ1 proteins share sequence similarity with those regions of SIS1, a yeast homolog of DnaJ. Western blot analysis of human brain homogenates using antibodies against HSJ1 detected proteins with apparent molecular masses of approximately 42 and 36 kD. RNase protection analysis showed that HSJ1 is expressed almost exclusively in the brain, with the highest levels in the frontal cortex and hippocampus. In situ hybridization of human brain sections detected HSJ1 mRNA mainly in the neuronal layers.