Optineurin

Optineurin (OPTN) is a multifunctional protein of 577 amino acids that plays important roles in Golgi maintenance, membrane trafficking, and exocytosis through interactions with myosin VI and Rab8 (UniProt: Q96CV9). It also functions as an autophagy receptor targeting ubiquitin-coated cargo including bacteria, and participates in innate immune signaling by recruiting TBK1 to the Golgi apparatus during viral infection.

In the nervous system, optineurin is implicated in several neurodegenerative conditions. UniProt disease associations include glaucomas (open angle and normal pressure forms) and amyotrophic lateral sclerosis with or without frontotemporal dementia (ALS12), reflecting its neuroprotective roles in the eye and optic nerve and its involvement in cellular morphogenesis.

In Alzheimer's Disease, optineurin is downregulated in post-mortem AD brain tissue compared to age-matched controls (mean log2FC −0.221 in human post-mortem AD brain proteomics) (Chaparral AD proteomics). This reduction may reflect impaired autophagy or membrane trafficking capacity in the diseased brain, potentially contributing to pathogenic accumulation of protein aggregates characteristic of AD.