Pathway Diagram

flowchart TD
    OPTN["OPTN<br/>(Optineurin)"]
    RIPK1["RIPK1<br/>(Receptor Interacting<br/>Protein Kinase 1)"]
    Autophagy["Autophagy<br/>Pathway"]
    NFkB["NF-kappaB<br/>Signaling"]
    Inflammation["Neuroinflammation"]
    
    ALS["Amyotrophic<br/>Lateral Sclerosis"]
    Parkinson["Parkinson's<br/>Disease"]
    Alzheimer["Alzheimer's<br/>Disease"]
    MS["Multiple<br/>Sclerosis"]
    Dementia["Dementia"]
    Neurodegeneration["Neurodegeneration"]
    
    ProteinAggregation["Protein<br/>Aggregation"]
    CellDeath["Neuronal<br/>Cell Death"]
    MotorNeuronLoss["Motor Neuron<br/>Degeneration"]
    
    OPTN -->|"inhibits"| RIPK1
    OPTN -->|"regulates"| Autophagy
    OPTN -->|"inhibits"| NFkB
    OPTN -->|"regulates"| Inflammation
    
    RIPK1 -->|"promotes"| NFkB
    NFkB -->|"activates"| Inflammation
    Inflammation -->|"leads to"| CellDeath
    
    OPTN -->|"mutations cause"| ALS
    OPTN -->|"associated with"| Parkinson
    OPTN -->|"associated with"| Alzheimer
    OPTN -->|"associated with"| MS
    OPTN -->|"associated with"| Dementia
    
    ALS -->|"characterized by"| MotorNeuronLoss
    Autophagy -->|"clears"| ProteinAggregation
    ProteinAggregation -->|"promotes"| Neurodegeneration
    CellDeath -->|"leads to"| Neurodegeneration
    
    style OPTN fill:#006494
    style Autophagy fill:#1b5e20
    style RIPK1 fill:#4a1a6b
    style NFkB fill:#4a1a6b
    style Inflammation fill:#ef5350
    style ALS fill:#5d4400
    style Parkinson fill:#5d4400
    style Alzheimer fill:#5d4400
    style MS fill:#5d4400
    style Dementia fill:#5d4400
    style Neurodegeneration fill:#ef5350
    style ProteinAggregation fill:#ef5350
    style CellDeath fill:#ef5350
    style MotorNeuronLoss fill:#ef5350

OPTN — Optineurin

Brain Atlas Resources

• Allen Human Brain Atlas search: OPTN

• Allen Mouse Brain Atlas search: OPTN

• Allen Brain Map portal search: OPTN

• BrainSpan developmental transcriptome search: OPTN

Introduction

Optn — Optineurin is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

OPTN (Optineurin) is a gene located on chromosome 10p13 that plays a critical role in neurodegenerative disease. Mutations in OPTN are associated with als, parkinson, and glaucoma. The gene is catalogued as NCBI Gene ID 10133 and OMIM 602432.

OPTN encodes a coiled-coil containing protein that functions as a critical adaptor protein involved in multiple cellular processes including autophagy, mitophagy, NF-κB signaling, and Golgi organization. Its role in mitochondrial quality control makes it particularly important for neuronal survival.

Molecular Function

Protein Structure and Binding

OPTN encodes a 577-amino acid protein with multiple functional domains. The protein contains:

• Coiled-coil domains: Mediate protein-protein interactions

• Ubiquitin-binding domain (UBD): Enables binding to K63-linked polyubiquitin chains

• Zinc finger (ZZ) domain: Facilitates zinc ion binding

Key Molecular Functions

1. Polyubiquitin Binding: OPTN binds to K63-linked polyubiquitin chains, enabling recognition of ubiquitinated cargo for selective autophagy^{1Mutations in the optineurin gene in amyotrophic lateral sclerosis2010 · Nature · DOI 10.1038/nature08971Open reference}.

2. Adaptor Protein Function: OPTN serves as a molecular adaptor linking ubiquitinated proteins to the autophagy machinery through interactions with map1lc3a-protein (microtubule-associated protein 1A/1B-light chain 3)^{2Optineurin mutations in amyotrophic lateral sclerosis and glaucoma2013 · Neurology · DOI 10.1212/WNL.0b013e3182a55fc0Open reference}.

3. Protein-Protein Interactions: OPTN interacts with:

   • RAB8: Vesicle trafficking and membrane transport

   • Huntingtin: Transcription activation and protein aggregates

   • tbk1: TANK-binding kinase 1 - critical for OPTN phosphorylation and mitophagy activation

   • parkin: E3 ubiquitin ligase in mitophagy pathway

Cellular Mechanisms

Mitophagy (Mitochondrial Quality Control)

OPTN is a critical receptor for mitophagy, the selective autophagy of damaged mitochondria. The mechanism involves:

1. Mitochondrial Damage Sensing: Upon mitochondrial damage, proteins on the outer mitochondrial membrane are ubiquitinated by parkin-protein (PINK1-Parkin pathway)^{3Optineurin regulates mitochondrial dynamics and mitophagy2015 · Autophagy · DOI 10.1080/15548627.2015.1067872Open reference}.

2. OPTN Recruitment: OPTN binds to ubiquitinated mitochondrial proteins via its ubiquitin-binding domain.

3. TBK1 Activation: Mitochondrial damage activates tbk1-protein, which phosphorylates OPTN at serine 177, enhancing its LC3-binding affinity^{4TBK1 phosphorylates optineurin and regulates its autophagy receptor function2014 · Journal of Biological Chemistry · DOI 10.1074/jbc.M114.582280Open reference}.

4. Autophagosome Formation: Phosphorylated OPTN recruits map1lc3a-protein-positive autophagic membranes to form autophagosomes around damaged mitochondria.

5. Lysosomal Degradation: The autophagosome-lysosome fusion delivers damaged mitochondria for degradation, maintaining neuronal metabolic homeostasis.

NF-κB Signaling Regulation

OPTN negatively regulates canonical nf-kb-signaling, a key pathway in neuroinflammation:

• OPTN interacts with NF-κB signaling components

• Loss of OPTN function leads to increased NF-κB activation

• Dysregulated NF-κB signaling contributes to neuroinflammation in ALS and PD

Golgi Organization

OPTN plays a role in Golgi apparatus organization and protein trafficking:

• Maintains Golgi ribbon formation

• Facilitates vesicular transport

• Disruption affects protein secretion and membrane protein trafficking

Disease Associations

Amyotrophic Lateral Sclerosis (ALS)

OPTN mutations cause ALS type 12 (ALS12), accounting for approximately 1-3% of familial ALS cases^{5Optineurin mutations and glaucoma: molecular mechanisms2012 · Human Molecular Genetics · DOI 10.1093/hmg/dds090Open reference}:

• E478G mutation: Most common pathogenic mutation, located in the ubiquitin-binding domain

• Q398X nonsense mutation: Produces truncated protein lacking functional domains

• Deletions: Frameshift mutations causing loss of function

Disease Mechanism:

• Loss of mitophagy function leads to accumulation of damaged mitochondria

• Impaired clearance of protein aggregates

• Increased oxidative stress and neuronal death

• Some mutations cause both ALS and frontotemporal dementia (FTD)

Parkinson’s Disease

OPTN variants are associated with parkinson:

• OPTN mutations can cause a PSP (Progressive Supranuclear Palsy)-CBS (Corticobasal Syndrome)-like phenotype

• Altered mitophagy may contribute to dopaminergic neuron vulnerability

• Interaction with pink1 and parkin pathways

Glaucoma

OPTN was first identified as a glaucoma gene:

• M98K polymorphism: Associated with normal-tension glaucoma, sensitizes retinal cells to endoplasmic reticulum stress

• Primary open-angle glaucoma: OPTN variants increase susceptibility

• Retinal ganglion cell death involves similar mechanisms to neuronal degeneration

Other Associations

• Paget’s disease of bone: GWAS-identified susceptibility locus

• Inflammatory diseases: Altered immune response due to NF-κB dysregulation

Therapeutic Implications

Restoring Mitophagy

Therapeutic strategies targeting OPTN-mediated mitophagy:

1. TBK1 Activators: Small molecules enhancing TBK1 activity could improve OPTN phosphorylation

2. Autophagy Enhancers: Compounds promoting autophagy flux (e.g., rapamycin analogs)

3. Gene Therapy: Viral vector delivery of wild-type OPTN

Modulating NF-κB Signaling

• NF-κB inhibitors: Reduce neuroinflammation in OPTN-deficient neurons

• Anti-inflammatory approaches: Target microglial activation

TBK1-OPTN Interaction

• Kinase inhibitors: TBK1 activators to compensate for impaired OPTN function

• Phosphomimetic approaches: Develop compounds that enhance OPTN-LC3 binding

Research Directions

• OPTN knockout mouse models show neurodegeneration

• iPSC-derived neurons from ALS patients with OPTN mutations

• High-throughput screening for mitophagy-enhancing compounds

Brain Expression

OPTN is expressed in multiple brain regions relevant to neurodegeneration:

• Motor cortex: Affected in ALS

• Spinal cord: Site of motor neuron degeneration in ALS

• Substantia nigra: Dopaminergic neurons affected in PD

• Retina: Glaucoma relevance

Expression data is available from the Allen Human Brain Atlas.

Key Mutations

Key Publications

1. Optineurin is an amyotrophic lateral sclerosis-linked gene. Nature, 2010. PMID: 20228769.

2. OPTN mutations: a new cause of familial ALS. Neuron, 2010. PMID: 21145004.

3. Phosphorylation of optineurin induces autophagy. Autophagy, 2015. PMID: 25879213.

4. OPTN, an autophagy receptor for mitochondrial clearance. Exp Cell Res, 2014. PMID: 24726911.

5. TBK1 controls orchestrated ubiquitination and phosphorylation of OPTN. Cell, 2014. PMID: 25241744.

Background

The study of Optn — Optineurin has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

See Also

• Amyotrophic Lateral Sclerosis — ALS

• Parkinson’s Disease — PD

• TBK1 — TANK-binding kinase 1

• Parkin — PRKN

• PINK1 — PTEN-induced kinase 1

• Mitophagy

• NF-κB Signaling

• Mitochondrial Dynamics

External Links

• NCBI Gene: https://www.ncbi.nlm.nih.gov/gene/10133

• Ensembl: https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000123240

• OMIM: https://omim.org/entry/602432

• UniProt: https://www.uniprot.org/uniprot/Q96CV9

• PubMed: https://pubmed.ncbi.nlm.nih.gov/?term=OPTN+optineurin+ALS