Ras-related protein Rab-4A

RAB4A encodes Ras-related protein Rab-4A, a small GTPase that regulates intracellular membrane trafficking by cycling between inactive GDP-bound and active GTP-bound states. It recruits downstream effectors responsible for vesicle formation, movement, tethering, and fusion. RAB4A specifically mediates protein transport and vesicular traffic, including VEGFR2 endosomal trafficking to enhance VEGFR2 signaling, and regulates platelet alpha-granule release (UniProt: P20338).

RAB4A is involved in receptor signaling and membrane dynamics across multiple cellular compartments, functions critical to neuronal physiology and synaptic transmission.

RAB4A is upregulated in Alzheimer's Disease brain tissue. Chaparral AD proteomics analysis of human post-mortem AD brain compared to age-matched controls detected RAB4A elevation with a mean log2 fold-change of +0.25 across one subcellular fraction in TMT-labeled proteomics data (Chaparral AD proteomics). This upregulation may reflect compensatory or pathological changes in endosomal trafficking and vesicular dynamics associated with AD neuropathology.