DnaJ heat shock protein family member C21 (DNAJC21)

DnaJ heat shock protein family member C21 (DNAJC21) is a ubiquitously expressed nuclear and cytoplasmic co-chaperone involved mainly in rRNA biogenesis and the maturation of the 60S ribosomal subunit. DNAJC21 binds precursor 45S rRNA, associates with key cofactors such as PA2G4, ZNF622, and HSPA8, and is essential for proper nucleo-cytoplasmic transport and final maturation of ribosomal subunits. Germline mutations cause a cancer-prone bone marrow failure syndrome, manifesting as hematopoietic defects, cytopenia, impaired cell growth, and increased disease risk, particularly acute myeloid leukemia. Deficits in DNAJC21 lead to abnormal ribosome profiles, cell death, and increased sensitivity to ribosome synthesis inhibitors, highlighting its fundamental role in cellular protein homeostasis and human disease[1][2][3].

Other names

DnaJ homolog subfamily C member 21DNAJC21DNAJA5GS3JJJ1BMFS3Protein GS3DnaJ (Hsp40) homolog subfamily C member 21DnaJ homology subfamily A member 5JJJ1 DnaJ domain protein homologDnaJ homolog subfamily A member 5[3]

Drugs that affect ribosomal RNA synthesis (such as Actinomycin D) can have increased cytotoxicity in DNAJC21-deficient cells due to impaired rRNA biogenesis[1]