DnaJ homolog subfamily C member 5, also known as cysteine string protein or CSP is a protein, that in humans encoded by the DNAJC5 gene.

This gene is a member of the J protein family. J proteins function in many cellular processes by regulating the ATPase activity of 70 kDa heat shock proteins. The encoded protein plays a role in membrane trafficking and protein folding, and has been shown to have anti-neurodegenerative properties. The encoded protein is known to play a role in cystic fibrosis and Huntington's disease. A pseudogene of this gene is located on the short arm of chromosome 8. [provided by RefSeq, Nov 2010]. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications.
Function: May have an important role in presynaptic function. May be involved in calcium-dependent neurotransmitter release at nerve endings (By similarity).