Glomulin

Glomulin (GLMN) is a regulatory component of SCF (SKP1-Cullin-F-box protein) E3 ubiquitin-protein ligase complexes that inhibits their activity by binding to RBX1 and blocking interaction with the E2 ubiquitin-conjugating enzyme CDC34 (UniProt: Q92990). It regulates neddylation of cullins and maintains stability of key SCF complex components, including FBXW7, RBX1, and various cullin family members, thereby controlling levels of CCNE1 and MYC. The protein is also essential for normal vascular development and contributes to RPS6KB1 phosphorylation regulation (UniProt: Q92990).

Glomulin is associated with glomuvenous malformations (GVMs), a vascular disorder characterized by abnormal glomus cells in vessel walls (UniProt: Q92990). Its role in vascular development and ubiquitin-ligase regulation suggests broader importance in vascular and cellular homeostasis.

In Alzheimer's disease, glomulin is significantly down-regulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of −0.76 across measured subcellular fractions (Chaparral AD proteomics). This reduction may reflect dysregulation of SCF-mediated protein degradation pathways implicated in AD neurodegeneration, though the mechanistic significance requires further investigation.