DnaJ heat shock protein family (Hsp40) member C5
The DNAJC5 provides instructions for making a protein called cysteine string protein alpha (CSPα). This protein is found in the brain, where it plays a role in the transmission of nerve impulses. CSPα helps sac-like structures called synaptic vesicles attach to nerve cells. Synaptic vesicles contain chemical messengers that transmit signals from one nerve cell to another.
Researchers suspect that CSPα may also help repair proteins that are involved in the transmission of nerve impulses by re-folding any that have the incorrect 3-dimensional shape.
At least two mutations in the DNAJC5 gene have been found to cause Kufs disease type B. This condition is a type of neuronal ceroid lipofuscinosis (NCL) characterized by progressive problems with movement and a decline in intellectual function beginning in adulthood. One mutation replaces the protein building block (amino acid) leucine with the amino acid arginine at position 115 in the CSPα protein (written as L115R). The other mutation deletes the amino acid leucine at position 116 in the protein (written as L116del). These DNAJC5 gene mutations occur in one copy of the gene in each cell and lead to the production of an altered protein that does not associate with the synaptic vesicle, resulting in impaired nerve impulse transmission. Additionally, abnormal CSPα may attach (bind) to normal CSPα and prevent the protein from associating with synaptic vesicles, further impairing nerve impulse transmission.
In Kufs disease, fatty substances called lipopigments accumulate in the lysosomes of nerve cells (neurons) in the brain. These accumulations can result in cell dysfunction and eventually cause cell death. The progressive death of neurons contributes to the signs and symptoms of Kufs disease. However, it is unclear how mutations in the DNAJC5 gene are involved in the buildup of lipopigments and how impaired nerve impulse transmissions contribute to the signs and symptoms of Kufs disease.
- cysteine string protein alpha
- DnaJ (Hsp40) homolog, subfamily C, member 5
- dnaJ homolog subfamily C member 5