HSJ1, or DnaJ heat shock protein family (Hsp40) member B2, is a human gene encoded by DNAJB2. It may also be known as: DnaJ homolog subfamily B member 2; Heat shock 40 kDa protein 3; Heat shock protein J1; HSJ-1; DSMA5; DnaJ (Hsp40) homolog, subfamily B, member 2; HSPF3. The encoded protein has an amino acid length of 324 and a mass of 35.6 kDa. Other isoforms may exist. Homologs of this gene exist in other organisms, including: Zebrafish, Chicken.