RalA-binding protein 1

RalA-binding protein 1 (RALBP1) is a multifunctional protein that acts as a downstream effector of the small GTPases RALA and RALB (UniProt: Q15311). The protein functions as a GTPase-activating protein that inactivates CDC42 and RAC1, regulates receptor-mediated endocytosis during interphase, and serves as a scaffold protein during mitosis. RALBP1 also has ATP-dependent transporter activity for glutathione conjugates and xenobiotics, potentially contributing to multidrug resistance.

RALBP1 localizes to mitochondria and is involved in several cellular processes including mitotic progression, mitochondrial fission, and endocytic regulation through the RAL signaling pathway (UniProt: Q15311). The protein has been implicated in cell cycle control and receptor trafficking mechanisms.

In Alzheimer's disease, RALBP1 is consistently upregulated in human post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.48 across subcellular fractions from TMT-labeled proteomics analysis (Chaparral AD proteomics). This upregulation suggests a potential role in AD pathophysiology, though the specific mechanistic contribution remains to be clarified.