Coiled-coil domain-containing protein 91

CCDC91 (coiled-coil domain-containing protein 91) is a 441-amino acid protein involved in the regulation of membrane traffic through the trans-Golgi network (TGN), where it functions cooperatively with GGAs in sorting hydrolases to lysosomes (UniProt: Q7Z6B0).

The protein localizes to the secretory pathway and participates in lysosomal protein sorting, critical functions for cellular homeostasis and autophagy. No baseline disease associations are documented in UniProt for this protein.

In Alzheimer's disease, CCDC91 shows consistent downregulation in post-mortem AD brain tissue compared to age-matched controls (mean log2FC: −0.5064), as measured across subcellular fractions in TMT-labeled proteomics (Chaparral AD proteomics). The reduced abundance of this TGN-trafficking regulator in AD brain may reflect impaired lysosomal protein sorting or broader disruptions in membrane trafficking pathways characteristic of neurodegeneration.