GIT1 Isoform 3 Summary

GIT1 (ARF GTPase-activating protein GIT1) is an isoform of a protein that regulates ARF GTPase signaling through catalytic inactivation of ARF family small GTPases (UniProt: Q9Y2X7-3). The protein functions as a GAP (GTPase-activating protein) and is involved in cellular signaling processes that regulate membrane trafficking and cytoskeletal dynamics.

GIT1 is ubiquitously expressed and participates in multiple cellular pathways governing actin dynamics and vesicular transport. The canonical protein has been implicated in neuronal morphogenesis and synaptic regulation, functions particularly relevant to brain tissue.

This isoform is associated with Alzheimer's Disease and shows consistent downregulation in AD pathology. In post-mortem AD brain tissue compared to age-matched controls, GIT1 isoform 3 exhibits decreased abundance with a mean log2 fold-change of −0.45 across measured subcellular fractions (Chaparral AD proteomics, TMT-labeled quantitative proteomics from P2, P3, S2, and S3 fractions). The downregulation suggests potential involvement in AD-related synaptic or cellular dysfunction mechanisms.