Hepatocyte growth factor-regulated tyrosine kinase substrate

Hepatocyte growth factor-regulated tyrosine kinase substrate (HGS) is a 777-amino-acid protein that functions in intracellular signal transduction downstream of cytokines and growth factors. It plays a central role in endocytic trafficking and receptor downregulation by serving as a component of the ESCRT-0 complex, which recognizes ubiquitinated receptors and directs them toward lysosomal degradation via multivesicular bodies. HGS also regulates early endosome function and receptor recycling pathways (UniProt: O14964).

HGS is broadly involved in vesicular trafficking and the internalization of growth factor receptors across multiple cellular compartments. The protein's association with STAM protein is critical for suppressing DNA signaling and concentrating ubiquitinated cargo within clathrin-coated regions, connecting it to fundamental processes in receptor homeostasis and signal attenuation.

In Alzheimer's Disease, HGS shows ambiguous regulation across subcellular fractions in post-mortem AD brain tissue relative to age-matched controls, with a mean log2 fold-change of −0.0867 (Chaparral AD proteomics). This modest and inconsistent change across the four fractions examined suggests HGS involvement may vary by cellular compartment in AD pathology, though no consistent direction of dysregulation emerged from the analysis.