Enables misfolded protein binding activity. Involved in several processes, including detection of misfolded protein; gene expression; and proteasome-mediated ubiquitin-dependent protein catabolic process. Located in nucleus. Part of cytosolic small ribosomal subunit. Is active in cytosol and nucleolus. Used to study autosomal dominant limb-girdle muscular dystrophy type 1 and congenital myopathy 21. Human ortholog(s) of this gene implicated in congenital myopathy 21 and primary ciliary dyskinesia 34. Orthologous to several human genes including DNAJB1 (DnaJ heat shock protein family (Hsp40) member B1).
SGD Description
Type II HSP40 co-chaperone that interacts with the HSP70 protein Ssa1p; shuttles between cytosol and nucleus; mediates delivery of misfolded proteins into the nucleus for degradation; involved in proteasomal degradation of misfolded cytosolic proteins; protein abundance increases in response to DNA replication stress; polyQ aggregates sequester Sis1p and interfere with clearance of misfolded proteins; similar to bacterial DnaJ proteins and mammalian DnaJB1