Ras-related protein Rab-22A

RAB22A encodes Ras-related protein Rab-22A, a small GTPase that regulates intracellular membrane trafficking and vesicle dynamics. As a key Rab protein, it cycles between GDP-bound (inactive) and GTP-bound (active) states to recruit effectors responsible for vesicle formation, movement, tethering, and fusion (UniProt: Q9UL26). RAB22A specifically mediates transferrin trafficking from early endosomes to recycling endosomes and is required for NGF-dependent NTRK1 endocytosis and neurite outgrowth, reflecting its importance in neuronal signaling.

RAB22A functions in endocytic pathways central to neuronal protein homeostasis and growth factor responses. Its role in receptor-mediated endocytosis and recycling makes it relevant to synaptic plasticity and neuronal development (UniProt: Q9UL26).

In Alzheimer's disease, RAB22A is significantly downregulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of −0.81 (Chaparral AD proteomics). This reduction in a protein essential for intracellular trafficking and neurotrophic signaling may contribute to impaired endosomal function and protein clearance mechanisms implicated in AD pathology.