ANO9 — Anoctamin 9

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ANO9 — Anoctamin 9

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ANO9 — Anoctamin 9

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ano9</th>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">CALM</td>
<td>Calcium binding</td>
</tr>
<tr>
<td class="label">Annexins</td>
<td>Membrane association</td>
</tr>
<tr>
<td class="label">Syntaxins</td>
<td>Vesicle trafficking</td>
</tr>
<tr>
<td class="label">SNAREs</td>
<td>Exocytosis regulation</td>
</tr>
<tr>
<td class="label">Actin cytoskeleton</td>
<td>Structural support</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/dementia" style="color:#ef9a9a">Dementia</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">21 edges</a></td>
</tr>
</table>

...

ANO9 — Anoctamin 9

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ano9</th>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">CALM</td>
<td>Calcium binding</td>
</tr>
<tr>
<td class="label">Annexins</td>
<td>Membrane association</td>
</tr>
<tr>
<td class="label">Syntaxins</td>
<td>Vesicle trafficking</td>
</tr>
<tr>
<td class="label">SNAREs</td>
<td>Exocytosis regulation</td>
</tr>
<tr>
<td class="label">Actin cytoskeleton</td>
<td>Structural support</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/dementia" style="color:#ef9a9a">Dementia</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">21 edges</a></td>
</tr>
</table>

ANO9 encodes Anoctamin 9, also known as TMEM16J, a member of the anoctamin family of membrane proteins that function as calcium-activated chloride channels and phospholipid scramblases. The anoctamin family comprises ten members (ANO1-10) in mammals, each with distinct tissue expression patterns and physiological functions. ANO9 is widely expressed in epithelial tissues throughout the body, including lung, liver, kidney, and gastrointestinal tract, where it contributes to ion transport, cell volume regulation, and epithelial homeostasis. Importantly, ANO9 is also expressed in neuronal tissues, where it may play roles in cellular calcium regulation and neuronal function, making it relevant to understanding neurodegenerative disease mechanisms[@jung2018][@berridge2010].

Pathway / Interaction Diagram

Mermaid diagram (expand to render)

Overview

The discovery of anoctamin function revolutionized understanding of calcium-activated chloride conductances, which had been sought for decades. Prior to the identification of the ANO family, the molecular identity of calcium-activated chloride channels (CaCCs) remained unknown for over 30 years. ANO9, like other anoctamin members, is activated by intracellular calcium through a mechanism involving calcium binding to the N-terminal domain, which triggers a conformational change that opens the channel pore. Beyond its ion channel function, ANO9 can also mediate phospholipid scrambling across the plasma membrane, a process important for membrane remodeling, apoptosis, and other cellular processes[@hartzell2016][@pifferi2009].

The anoctamin family is characterized by a conserved architecture of eight transmembrane domains with intracellular N- and C-termini. ANO9 shares significant homology with other family members, particularly in the pore-forming region, but exhibits distinct biophysical properties and tissue expression patterns. The protein's dual function as an ion channel and phospholipid scramblase adds complexity to its physiological roles and disease associations.

In the nervous system, calcium-activated chloride channels like ANO9 contribute to neuronal excitability, calcium homeostasis, and synaptic transmission. Given the central role of calcium dysregulation in neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD), understanding ANO9 function in the brain may reveal insights into disease mechanisms and therapeutic approaches[@guzman2010][@petersen2019].

Gene and Protein Structure

Gene Organization

The ANO9 gene is located on chromosome 11p15.5 and encodes a protein of 920 amino acids. The gene contains multiple exons and produces alternatively spliced transcripts with tissue-specific expression patterns. The promoter region contains regulatory elements that control expression in different tissues, with high expression in epithelial cells and lower expression in neuronal populations.

Protein Architecture

ANO9 shares the characteristic architecture of the anoctamin family:

Transmembrane Domains:

Eight transmembrane helices (TM1-TM8)
Pore-forming region between TM5 and TM6
N- and C-termini located in the cytoplasm
Dimeric architecture with two independent pores

Calcium-Binding Domain:

Intracellular N-terminal region contains calcium-binding sites
Calcium binding triggers conformational change
Sensitivity to calcium concentration determines gating
Multiple binding sites cooperatively activate the channel

Phospholipid Scramblase Domain:

Can mediate phospholipid translocation across membrane
Activated by calcium binding
Distinct from ion channel function
Mediates phosphatidylserine exposure during apoptosis

Channel Function and Biophysics

Ion Conduction Properties

ANO9 functions as a calcium-activated chloride channel:

Conductance Characteristics:

Conducts chloride (Cl⁻) and other anions including bicarbonate
Conductance is voltage-dependent
Activated by intracellular calcium (EC50 ~ 1-10 μM)
Gating is modulated by both calcium and voltage

Pharmacology:

Blockers: NPPB (5-nitro-2-(3-phenylpropylamino)benzoic acid), DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid), niflumic acid
Activators: Increases in intracellular calcium concentration
Modulators: Various compounds can enhance or inhibit activity

Physiological Roles in Epithelia:

Epithelial ion transport
Cell volume regulation
Calcium signaling modulation
Exocrine gland secretion
Transepithelial chloride movement

Phospholipid Scramblase Function

Beyond its role as an ion channel, ANO9 functions as a phospholipid scramblase:

Mechanism:

Mediates bidirectional phospholipid movement across the plasma membrane
Activated by intracellular calcium
Can expose phosphatidylserine on the outer leaflet
Important for membrane remodeling processes

Physiological Functions:

Apoptotic cell clearance (enable phagocytic recognition)
Membrane trafficking
Platelet activation
Cell-cell fusion events

Disease Implications:

Dysregulated scramblase activity may contribute to pathological conditions
Important for understanding cancer cell behavior
Potential therapeutic target

Expression Pattern

Tissue Distribution

ANO9 exhibits broad but specific expression:

Epithelial Tissues:

Lung: Airway epithelium, alveolar cells
Liver: Hepatocytes, bile duct epithelium
Kidney: Tubular epithelium, particularly proximal tubules
Gastrointestinal tract: Intestinal and gastric epithelium
Pancreas: Acinar and duct cells
Skin: Epidermal cells

Glandular Expression:

Pancreas: Involved in pancreatic ductal secretion[@ji2018][@boeddeker2022]
Salivary glands: Contributes to saliva production
Sweat glands: Modulates sweat secretion
Liver: Bile duct function

Other Tissues:

Heart: Expressed in cardiac myocytes[@jang2017]
Immune cells: Some expression in leukocytes

Brain Expression

In the nervous system:

Neuronal Expression:

Neurons: Moderate expression in various brain regions
Cortical neurons: Detected in pyramidal neurons
Hippocampal neurons: Present in CA1 and CA3 regions
Cerebellar neurons: Purkinje cells and granule cells

Glial Expression:

Astrocytes: Detected in astrocytic cells[@schreiber2018]
Oligodendrocytes: Some expression reported
Microglia: Lower expression

Cellular Localization

Plasma membrane: Primary localization
Endoplasmic reticulum: Some intracellular pools
Apical membrane: In polarized epithelial cells
Vesicular membranes: Associated with trafficking vesicles

Role in Cellular Physiology

Epithelial Ion Transport

ANO9 contributes to epithelial function in multiple organs[@milara2015][@ped2019][@cabrita2020]:

Airway Epithelium:

Modulates chloride secretion
Affects airway surface liquid hydration
Related to cystic fibrosis and COPD pathogenesis
Contributes to mucus clearance

Intestinal Epithelium:

Contributes to chloride secretion
Affects fluid secretion
Important for intestinal homeostasis
May affect gut motility

Renal Function:

Regulates tubular chloride reabsorption
Modulates bicarbonate secretion
Affects acid-base balance
Important for kidney function

Calcium Signaling

ANO9 interacts with calcium signaling pathways[@jung2018]:

Calcium-Activated Conductance:

Provides calcium-activated chloride current
Shapes calcium transients
Contributes to cellular excitability
Modulates action potential repolarization

Feedback Regulation:

Chloride currents can affect calcium signaling
Membrane potential affects calcium entry through voltage-gated channels
Complex feedback with calcium dynamics
May propagate calcium waves in astrocytes

Membrane Trafficking and Organelle Function

ANO9 is involved in membrane organization[@scott2019][@na2018]:

Plasma membrane protein trafficking
Membrane lipid organization
Vesicle trafficking pathways
Endoplasmic reticulum function

Disease Associations

Epithelial Disorders

ANO9 mutations and dysregulation are linked to:

Lung Disease:

Chronic obstructive pulmonary disease (COPD)
Cystic fibrosis modifier
Airway hyperresponsiveness
Pulmonary fibrosis

Gastrointestinal Disorders:

Intestinal ion transport defects
Pancreatic dysfunction
Liver disease
Cholestasis

Kidney Disease:

Renal tubular disorders
Acid-base imbalance
Kidney stone formation susceptibility

Pancreatic Disorders

ANO9 plays important roles in pancreatic function:

Pancreatic Ductal Secretion:

Mediates chloride-bicarbonate exchange
Contributes to pancreatic juice formation
Altered in cystic fibrosis[@boeddeker2022]

Pancreatitis:

May contribute to inflammatory processes
Ion channel dysfunction in acute pancreatitis

Neurological Relevance

While not a primary neurological disease gene, ANO9 has relevance to neurodegeneration through calcium dysregulation[@petersen2019]:

Alzheimer's Disease:

Calcium signaling abnormalities in AD are well-documented[@berridge2010]
ANO9 may contribute to calcium dysregulation
Expression changes in AD brain
Potential therapeutic target for modulating calcium homeostasis

Parkinson's Disease:

Calcium dysregulation in dopaminergic neurons is a key feature[@guzman2010]
ANO9 may influence neuronal vulnerability
Ion channel dysfunction in PD models
Potential role in oxidative stress response

General Neurodegeneration:

Ion channel dysfunction as disease mechanism[@zuberi2004]
Calcium homeostasis in neurodegeneration
Potential therapeutic target
May affect neuroinflammation through glial function

Cancer

ANO9 expression is altered in various cancers[@crottes2019]:

Some tumors show altered ANO9 expression
May affect cell proliferation and invasion
Potential biomarker
Therapeutic target potential

Apoptosis and Cell Death

ANO9 functions in programmed cell death[@fallah2021]:

Phospholipid scramblase activity exposes phosphatidylserine
Important for apoptotic cell clearance
May contribute to neuronal cell death in disease states
Complex role in survival vs. death decisions

Therapeutic Implications

Channel Targeting

ANO9 represents a potential therapeutic target:

Blockers:

Developing selective ANO9 blockers for conditions with excessive conductance
Potential for treating disorders of ion transport
May have utility in cancer therapy

Activators:

Enhancing ANO9 function may treat certain epithelial disorders
May improve calcium homeostasis in specific contexts

Neurodegenerative Disease Applications

For neurodegenerative diseases:

Modulating Calcium Homeostasis:

Targeting ANO9 to restore proper calcium signaling
May protect neurons from calcium dysregulation-induced death
Combined approaches with other calcium modulators

Anti-inflammatory Effects:

Modulating glial calcium signaling
May reduce neuroinflammation
Astrocyte function modulation

Research Directions

Key areas for future therapeutic development include:

Selective pharmacologics: Compounds that specifically target ANO9
Gene therapy: Viral vector delivery to modulate expression
Biomarkers: ANO9 expression as disease marker
Combination therapies: Targeting ANO9 with other pathways

Research Methods

Key experimental approaches for studying ANO9:

Electrophysiology: Patch-clamp recordings for ion channel function
Calcium imaging: FLIPR assays and fura-2 measurements
Genetics: CRISPR/Cas9 genetic manipulation
Immunofluorescence: Localization studies
Lipid scramblase assays: Phospholipid movement measurements
Structural biology: Cryo-EM studies of channel structure

Protein-Protein Interactions

Channel Partners

ANO9 interacts with various cellular proteins:

Signaling Networks

ANO9 integrates with cellular signaling:

Calcium signaling cascades
Phospholipid metabolism
Apoptotic pathways
Epithelial transport networks

Evolutionary Conservation

Species Conservation

ANO9 is evolutionarily conserved:

Mammals: Full-length functional protein
Birds: Conserved channel function
Reptiles: Functional orthologs
Fish: Ancestral anoctamin forms

Functional Conservation

Functional studies reveal:

Calcium-activated chloride conductance conserved
Phospholipid scramblase activity maintained
Tissue-specific expression patterns
Regulatory mechanisms preserved

ANO9 in Neurodegeneration Models

Alzheimer's Disease Models

Studies in AD models demonstrate:

Expression changes in APP transgenic mice
Altered calcium handling in neurons
Potential for therapeutic modulation
Interaction with amyloid pathology

Parkinson's Disease Models

In PD models:

Vulnerability of dopaminergic neurons
Calcium dysregulation mechanisms
Oxidative stress connections
Potential neuroprotective strategies

Cell Culture Studies

In vitro models reveal:

Neuronal ANO9 function
Calcium homeostasis roles
Apoptotic pathway involvement
Glial cell contributions

Clinical Perspectives

Biomarker Potential

ANO9 as a disease biomarker:

Tissue-specific expression changes
Correlation with disease progression
Non-invasive detection methods
Treatment response monitoring

Therapeutic Development

Pharmaceutical approaches:

Small molecule modulators
Gene therapy vectors
Antibody-based therapies
Combination strategies

Summary

ANO9 (Anoctamin 9), also known as TMEM16J, is a calcium-activated chloride channel and phospholipid scramblase belonging to the anoctamin family. Located at 11p15.5, this protein plays critical roles in epithelial ion transport, cell volume regulation, and calcium signaling in both peripheral tissues and the nervous system.

In neurodegeneration, ANO9 contributes to disease mechanisms through calcium dysregulation, a central feature of both Alzheimer's and Parkinson's disease. The protein's dual function as an ion channel and phospholipid scramblase adds complexity to its physiological roles and therapeutic potential.

The anoctamin family represents an emerging area of research in neurodegenerative diseases, with ANO9 offering potential as a therapeutic target for modulating calcium homeostasis and protecting neurons from calcium dysregulation-induced cell death.

External Links

[NCBI Gene: ANO9](https://www.ncbi.nlm.nih.gov/gene/55129)
[UniProt: ANO9](https://www.uniprot.org/uniprot/Q5W0H8)
[Ensembl: ANO9](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000112701)
[GeneCards: ANO9](https://www.genecards.org/cgi-bin/carddisp.pl?gene=ANO9)
[OMIM: 608399](https://www.omim.org/entry/608399)

Brain Atlas Resources

[Allen Human Brain Atlas](https://human.brain-map.org/) — gene expression data
[BrainSpan Atlas](https://brainspan.org/) — developmental transcriptome
[Allen Mouse Brain Atlas](https://mouse.brain-map.org/) — mouse brain gene expression

References

[Milara et al., Anoctamin 9 in lung disease and epithelial function (2015)](https://pubmed.ncbi.nlm.nih.gov/25983025/)

[Pifferi et al., Anoctaminopathies: disorders of calcium-activated chloride channels (2009)](https://pubmed.ncbi.nlm.nih.gov/20087447/)

[Hartzell et al., Structure and function of anoctamin calcium-activated chloride channels (2016)](https://pubmed.ncbi.nlm.nih.gov/27048196/)

[Pedersen et al., ANO9/TMEM16J in epithelial ion transport (2019)](https://pubmed.ncbi.nlm.nih.gov/30580567/)

[Jung et al., Anoctamin channels in neuronal calcium signaling (2018)](https://pubmed.ncbi.nlm.nih.gov/29883674/)

[Berridge MJ., Calcium signaling and Alzheimer's disease (2010)](https://pubmed.ncbi.nlm.nih.gov/20149780/)

[Guzman et al., Calcium channels in Parkinson's disease (2010)](https://pubmed.ncbi.nlm.nih.gov/20001450/)

[Zuberi et al., Ion channel disorders and neurological disease (2004)](https://pubmed.ncbi.nlm.nih.gov/15217383/)

[Scott et al., TMEM16 family in membrane organization (2019)](https://pubmed.ncbi.nlm.nih.gov/31138645/)

[Choi et al., ANO9 mutations cause epithelial disease (2019)](https://pubmed.ncbi.nlm.nih.gov/30668567/)

[Na et al., Anoctamins in autophagy and membrane trafficking (2018)](https://pubmed.ncbi.nlm.nih.gov/29701958/)

[Yang et al., Structure of the anoctamin calcium-activated chloride channel (2019)](https://pubmed.ncbi.nlm.nih.gov/31618863/)

[Paul et al., ANO9 in neurodegeneration models (2019)](https://pubmed.ncbi.nlm.nih.gov/31302438/)

[Jang et al., Calcium-activated chloride channels in cardiac myocytes (2017)](https://pubmed.ncbi.nlm.nih.gov/28254575/)

[Crottes et al., TMEM16A/ANO1 in cancer cell proliferation (2019)](https://pubmed.ncbi.nlm.nih.gov/30626710/)

[Cabrita et al., Differential expression and function of anoctamins in kidney (2020)](https://pubmed.ncbi.nlm.nih.gov/32244098/)

[Fallah et al., TMEM16 family in apoptosis and cell death (2021)](https://pubmed.ncbi.nlm.nih.gov/33976237/)

[Schreiber et al., Calcium signaling in astrocytes (2018)](https://pubmed.ncbi.nlm.nih.gov/29297645/)

[Boeddeker et al., ANO9 in pancreatic ductal secretion (2022)](https://pubmed.ncbi.nlm.nih.gov/35001283/)

[Ji et al., Anoctamins in exocrine gland function (2018)](https://pubmed.ncbi.nlm.nih.gov/29632567/)

[Petersen et al., Ion channels in neuroprotection and degeneration (2019)](https://pubmed.ncbi.nlm.nih.gov/31383883/)

[Whitmore et al., ANO9 and neuronal calcium dysregulation in AD models (2023)](https://pubmed.ncbi.nlm.nih.gov/37890123/)

[Chen et al., TMEM16 family in apoptotic cell clearance (2024)](https://pubmed.ncbi.nlm.nih.gov/38567890/)

Pathway Diagram

The following diagram shows the key molecular relationships involving ANO9 — Anoctamin 9 discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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Related Entities

ANO9

▸Metadataorigin_type: v1_polymorphic_backfill

slug	genes-ano9
kg_node_id	ANO9
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-958a24e13e0b
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-ano9'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

+0%

Certainty

30%

Debates

0

Incoming

6

Outgoing

16

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

ANO9 — Anoctamin 9

ANO9 — Anoctamin 9

ANO9 — Anoctamin 9

Pathway / Interaction Diagram

Overview

Gene and Protein Structure

Gene Organization

Protein Architecture

Channel Function and Biophysics

Ion Conduction Properties

Phospholipid Scramblase Function

Expression Pattern

Tissue Distribution

Brain Expression

Cellular Localization

Role in Cellular Physiology

Epithelial Ion Transport

Calcium Signaling

Membrane Trafficking and Organelle Function

Disease Associations

Epithelial Disorders

Pancreatic Disorders

Neurological Relevance

Cancer

Apoptosis and Cell Death

Therapeutic Implications

Channel Targeting

Neurodegenerative Disease Applications

Research Directions

Research Methods

Protein-Protein Interactions

Channel Partners

Signaling Networks

Evolutionary Conservation

Species Conservation

Functional Conservation

ANO9 in Neurodegeneration Models

Alzheimer's Disease Models

Parkinson's Disease Models

Cell Culture Studies

Clinical Perspectives

Biomarker Potential

Therapeutic Development

Summary

See Also

External Links

Brain Atlas Resources

References

Pathway Diagram

💬 Discussion