Disease relevance of SCJ1

• The deduced protein sequence of the cloned gene revealed a polypeptide of 410 amino acids which is homologous to Escherichia coli DnaJ and the yeast DnaJ log SCJ1 [1].

High impact information on SCJ1

• The predicted amino-acid sequence of SCJ1 is 37% identical to the entire E. coli DnaJ protein [2].
• In contrast, deletion of JEM1 and SCJ1 had little effect on the ERAD of a membrane protein [3].
• We found that these ERAD substrates are stabilized and aggregate in the ER at elevated temperatures when BiP, the lumenal Hsp70 molecular chaperone, is mutated, or when the genes encoding the J domain-containing proteins Jem1p and Scj1p are deleted [3].
• A role for the DnaJ homologue Scj1p in protein folding in the yeast endoplasmic reticulum [4].
• Loss of Scj1p induces the unfolded protein response pathway, and results in a cell wall defect when combined with an oligosaccharyltransferase mutation [4].

Anatomical context of SCJ1

• We show that Scj1p is located in the lumen of the endoplasmic reticulum (ER), where it can function with Kar2p (the ER-lumenal BiP/Hsp70 of yeast) [5].

Other interactions of SCJ1

• The region common to all DnaJ homologues (termed the J domain) from Scj1p can be swapped for a similar region in Sec63p, which is known to interact with Kar2p in the ER lumen, to form a functional transmembrane protein component of the secretory machinery [5].

References