Ras-related protein Rab-11B

RAB11B (Ras-related protein Rab-11B) is a small GTPase that functions as a key regulator of intracellular membrane trafficking (UniProt: Q15907). It cycles between inactive GDP-bound and active GTP-bound states to recruit downstream effectors responsible for vesicle formation, movement, tethering, and fusion. RAB11B specifically regulates endocytic recycling of transmembrane proteins including CFTR, ENaC, and ion channels, and plays roles in constitutive and regulated secretion, melanosome transport, and ciliogenesis initiation through formation of ciliary targeting complexes.

RAB11B is expressed broadly and participates in membrane trafficking pathways essential for cellular homeostasis. A rare autosomal dominant neurodevelopmental disorder, neurodevelopmental disorder with ataxic gait, absent speech, and decreased cortical white matter (NDAGSCW; MIM 617807), has been associated with RAB11B mutations, presenting with severe intellectual disability, epilepsy, and white matter abnormalities (UniProt: Q15907).

In Alzheimer's Disease, RAB11B is significantly upregulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.19 across the analyzed subcellular fractions (Chaparral AD proteomics). This upregulation suggests a potential role for dysregulated membrane trafficking and vesicular recycling in AD pathogenesis, though the functional consequence requires further investigation.