Rab GDP dissociation inhibitor alpha

Rab GDP dissociation inhibitor alpha (Rab GDI alpha), encoded by GDI1, is a guanine nucleotide exchange regulator that inhibits GDP dissociation from Rab proteins and prevents their membrane activation (UniProt: P31150). It promotes the dissociation of GDP-bound Rab proteins, including RAB1A, RAB3A, RAB5A, and RAB10, from cellular membranes. This regulatory function is critical for controlling Rab-mediated vesicular transport and membrane trafficking dynamics.

The protein is expressed across tissues and plays a central role in intracellular membrane transport pathways. Beyond its role in vesicle trafficking, GDI1 has been associated with X-linked intellectual developmental disorder (XLID41), indicating its importance in neurodevelopmental processes (UniProt: P31150).

In Alzheimer's Disease, GDI1 is downregulated in post-mortem human AD brain tissue compared to age-matched controls, with a mean log2 fold-change of −0.1976 across subcellular fractions (Chaparral AD proteomics). This reduction may reflect compromised membrane trafficking and Rab protein regulation in AD pathology, potentially contributing to synaptic dysfunction and neurodegeneration characteristic of the disease.