Calnexin

Calnexin (CANX) is a calcium-binding chaperone protein located in the endoplasmic reticulum (ER) that plays a central role in protein quality control (UniProt: P27824). It interacts with newly synthesized monoglucosylated glycoproteins to assist in proper protein assembly and folding, retaining misfolded proteins within the ER to prevent their secretion. The protein also associates with T-cell antigen receptor complexes during thymocyte maturation and may participate in receptor-mediated endocytosis at the synapse.

Calnexin functions broadly in ER homeostasis and protein trafficking across multiple tissues, with particular importance in immune cell development and synaptic function. No disease associations are currently documented in UniProt.

Calnexin shows elevated abundance in Alzheimer's disease brain tissue, with a mean log2 fold-change of 1.41 compared to age-matched controls in post-mortem proteomics analysis (Chaparral AD proteomics). This upregulation suggests potential involvement in ER stress responses or protein misfolding pathways characteristic of AD pathology.