Plays an important role in the maintenance of the Golgi complex, in membrane trafficking, in exocytosis, through its interaction with myosin VI and Rab8 (PubMed:27534431). Links myosin VI to the Golgi complex and plays an important role in Golgi ribbon formation (PubMed:27534431). Plays a role in the activation of innate immune response during viral infection. Mechanistically, recruits TBK1 at the Golgi apparatus, promoting its trans-phosphorylation after RLR or TLR3 stimulation (PubMed:27538435). In turn, activated TBK1 phosphorylates its downstream partner IRF3 to produce IFN-beta. Plays a neuroprotective role in the eye and optic nerve. May act by regulating membrane trafficking and cellular morphogenesis via a complex that contains Rab8 and hungtingtin (HD). Mediates the interaction of Rab8 with the probable GTPase-activating protein TBC1D17 during Rab8-mediated endocytic trafficking, such as of transferrin receptor (TFRC/TfR); regulates Rab8 recruitment to tubules emanating from the endocytic recycling compartment. Autophagy receptor that interacts directly with both the cargo to become degraded and an autophagy modifier of the MAP1 LC3 family; targets ubiquitin-coated bacteria (xenophagy), such as cytoplasmic Salmonella enterica, and appears to function in the same pathway as SQSTM1 and CALCOCO2/NDP52. (Microbial infection) May constitute a cellular target for adenovirus E3 14.7 and Bluetongue virus protein NS3 to inhibit innate immune response. Self-associates (PubMed:23669351). Interacts with HD, Rab8 (RAB8A and/or RAB8B) (active GTP-bound form), GTF3A, TRAF3, TBK1, MYO6 and TFRC. Binds to linear ubiquitin chains. Interacts with LC3 family members MAP1LC3A, MAP1LC3B, GABARAP, GABARAPL1 and GABARAPL2; OPTN phosphorylation increases the association (at least with MAP1LC3B). Interacts with RAB12; the interaction may be indirect. Interacts with TBK1; this interaction leads to the Golgi localization of TBK1 and its subsequent activation. Interacts with palmitoyltransferase ZDHHC17/HIP14; the interaction does not lead to palmitoylation of OPTN (PubMed:24705354). Interacts with CYLD (PubMed:32185393). (Microbial infection) Interacts with E3 14.7 kDa protein of group C human adenovirus (PubMed:9488477). Interacts with Bluetongue virus protein NS3 (PubMed:27538435). Found in the perinuclear region and associates with the Golgi apparatus (PubMed:27534431). Colocalizes with MYO6 and RAB8 at the Golgi complex and in vesicular structures close to the plasma membrane. Localizes to LC3-positive cytoplasmic vesicles upon induction of autophagy. Present in aqueous humor of the eye (at protein level). Highly expressed in trabecular meshwork. Expressed nonpigmented ciliary epithelium, retina, brain, adrenal cortex, fetus, lymphocyte, fibroblast, skeletal muscle, heart, liver, brain and placenta. Upon TNF and interferon treatments. Up-regulated in direct response to viral infection. Ubiquitin-binding motif (UBAN) is essential for its inhibitory function, subcellular localization and interaction with TBK1. The LIR (LC3-interacting region) motif mediates the interaction with ATG8 family proteins. Phosphorylated by TBK1, leading to restrict bacterial proliferation in case of infection. Phosphorylation is induced by phorbol esters and decreases its half-time. The disease is caused by variants affecting the gene represented in this entry. Disease susceptibility is associated with variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. According to some authors (PubMed:12379221) its expression is regulated by intraocular pressure, suggesting a protective role in case of high pressure, while according to other authors (PubMed:12646749), it is not up-regulated in response to pressure elevation. Interaction of variant GLC1E LYS-50 with Rab8 is reported conflictingly. Coimmunoprecipitation experiments with overexpressed proteins suggested an increased interaction (PubMed:20085643) while yeast-two-hybrid (PubMed:22854040) and protein complentation assays with an equivalent mouse Optn construct (AC Q8K3K8) failed to show an interaction.