BAG1 Gene

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BAG1 Gene

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BAG1 - BCL-2-Associated Athanogene 1

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#f0f0f0; text-align:center;">BAG1</th></tr> [@zhang2005]
<tr><td><b>Full Name</b></td><td>BCL-Associated Athanogene 1</td></tr> [@wang2006]
<tr><td><b>Chromosomal Location</b></td><td>9q33.3</td></tr> [@mclear2008]
<tr><td><b>NCBI Gene ID</b></td><td>[573](https://www.ncbi.nlm.nih.gov/gene/573)</td></tr> [@gomezsantos2003]
<tr><td><b>OMIM</b></td><td>[602677](https://www.omim.org/entry/602677)</td></tr> [@kriel2018]
<tr><td><b>UniProt ID</b></td><td>[O95817](https://www.uniprot.org/uniprotkb/O95817/entry)</td></tr> [@patel2005]
<tr><td><b>Ensembl ID</b></td><td>[ENSG00000002172](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000102172)</td></tr> [@rezaizadeh2005]
<tr><td><b>Category</b></td><td>Molecular Chaperone</td></tr> [@biaoxue2014]
</table> [@muchowski2000]
</div> [@brodsky2014]

Overview

...

BAG1 - BCL-2-Associated Athanogene 1

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#f0f0f0; text-align:center;">BAG1</th></tr> [@zhang2005]
<tr><td><b>Full Name</b></td><td>BCL-Associated Athanogene 1</td></tr> [@wang2006]
<tr><td><b>Chromosomal Location</b></td><td>9q33.3</td></tr> [@mclear2008]
<tr><td><b>NCBI Gene ID</b></td><td>[573](https://www.ncbi.nlm.nih.gov/gene/573)</td></tr> [@gomezsantos2003]
<tr><td><b>OMIM</b></td><td>[602677](https://www.omim.org/entry/602677)</td></tr> [@kriel2018]
<tr><td><b>UniProt ID</b></td><td>[O95817](https://www.uniprot.org/uniprotkb/O95817/entry)</td></tr> [@patel2005]
<tr><td><b>Ensembl ID</b></td><td>[ENSG00000002172](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000102172)</td></tr> [@rezaizadeh2005]
<tr><td><b>Category</b></td><td>Molecular Chaperone</td></tr> [@biaoxue2014]
</table> [@muchowski2000]
</div> [@brodsky2014]

Overview

The BAG1 gene encodes Bcl-2-associated athanogene 1, a multi-functional co-chaperone protein that plays a critical role in regulating protein homeostasis, [apoptosis](/entities/apoptosis), and cellular stress responses. BAG1 is a member of the BAG family of co-chaperones, characterized by a conserved C-terminal BAG domain that mediates interaction with the ATPase domain of [Hsp70](/proteins/hsp70) family proteins. Through these interactions, BAG1 serves as a nucleotide exchange factor (NEF) that modulates the chaperone cycle and links the [Hsp70](/proteins/hsp70) system to various cellular processes including protein folding, degradation, and cell survival pathways [1]. [@nagai2003]

BAG1 is uniquely positioned at the intersection of protein quality control and apoptosis regulation, making it particularly relevant to neurodegenerative diseases where protein aggregation and neuronal cell death are hallmark features. The protein has been shown to protect [neurons](/entities/neurons) against various insults including oxidative stress, excitotoxicity, and proteasomal inhibition [2][3].

Molecular Function

BAG Domain and Hsp70 Interaction

The defining feature of BAG1 is its C-terminal BAG domain (approximately 110 amino acids), which forms a three-helix bundle that binds to the ATPase domain of [Hsp70](/proteins/hsp70) and [Hsc70](/proteins/hsp70) proteins [1]. This interaction stabilizes the ADP-bound state of Hsp70, effectively stimulating ATP hydrolysis and promoting substrate release. As a nucleotide exchange factor, BAG1 facilitates the recycling of Hsp70, enabling repeated rounds of substrate binding and release [4].

The BAG domain structure has been solved by X-ray crystallography, revealing a novel fold that interacts with the EEVD motif of Hsp70 proteins [5]. This molecular mechanism is conserved across species and is essential for BAG1's co-chaperone function.

Isoforms and Structure

The BAG1 gene produces multiple isoforms through alternative splicing, including BAG1M (BAG1L, 326 aa), BAG1S (BAG1, 259 aa), and other variants [6]. These isoforms differ in their N-terminal regions and cellular localization:

BAG1M/BAG1L: Contains a nuclear localization signal (NLS) and localizes to both cytoplasm and nucleus
BAG1S: Predominantly cytoplasmic isoform
BAG1M is the major isoform in neurons and has been shown to have potent neuroprotective properties [7]

All isoforms retain the C-terminal BAG domain, ensuring they can all interact with Hsp70 proteins.

Interaction Network

BAG1 interacts with numerous proteins beyond Hsp70:

| Partner Protein | Interaction Type | Functional Consequence |
|-----------------|------------------|------------------------|
| [BCL2](/proteins/bcl2-protein) | Direct binding | Anti-apoptotic, inhibits Bax activation |
| [Hsp70](/proteins/hsp70) | Co-chaperone | NEF activity, substrate release |
| Hsc70 | Co-chaperone | Protein folding, trafficking |
| Hsp90 | Co-chaperone | Steroid receptor maturation |
| Raf-1 | Direct binding | MAPK pathway modulation |
| IGF-1R | Direct binding | Cell survival signaling |
| p53 | Direct binding | Tumor suppression modulation |

Role in Neurodegeneration

Alzheimer's Disease

In [Alzheimer's disease](/diseases/alzheimers-disease) (AD), BAG1 plays a complex role in modulating both amyloid and [tau](/proteins/tau) pathology. BAG1 levels are altered in AD brain tissue, with some studies reporting decreased expression [8]. The protein interacts with tau phosphorylation pathways and may influence the clearance of hyperphosphorylated tau aggregates [9].

The Hsp70/BAG1 chaperone system is involved in:

Tau clearance: Hsp70, with BAG1 as its co-chaperone, can facilitate the ubiquitination and proteasomal degradation of hyperphosphorylated tau [10]
[Amyloid-beta](/proteins/amyloid-beta) handling: BAG1 influences [amyloid precursor protein](/entities/app-protein) (APP) processing and may affect Aβ generation [11]
Neuronal survival: BAG1 protects against Aβ-induced toxicity through anti-apoptotic mechanisms [12]

Parkinson's Disease

BAG1 has emerged as a potential therapeutic target in [Parkinson's disease](/diseases/parkinsons-disease) (PD) due to its neuroprotective effects on dopaminergic neurons. Studies have shown that BAG1 overexpression:

Protects against 6-hydroxydopamine (6-OHDA) toxicity [13]
Reduces caspase-3 activation in dopaminergic cell lines [14]
Modulates [α-synuclein](/proteins/alpha-synuclein) aggregation through Hsp70-mediated pathways [15]

The protein's anti-apoptotic function, mediated in part through interaction with [BCL2](/proteins/bcl2-protein) and inhibition of Bax translocation, is particularly relevant to the progressive loss of dopaminergic neurons in PD [16].

Amyotrophic Lateral Sclerosis

In amyotrophic lateral sclerosis (ALS), BAG1 expression levels correlate with motor neuron survival. The protein participates in:

Clearance of mutant SOD1 aggregates [17]
Protection against excitotoxicity [18]
Modulation of the [unfolded protein response](/entities/unfolded-protein-response) (UPR)

Expression Pattern

BAG1 is widely expressed throughout the brain with particularly high levels in:

[Cerebral cortex](/brain-regions/cortex) — especially layer V pyramidal neurons
[Hippocampus](/brain-regions/hippocampus) — CA1-CA3 regions and dentate gyrus
Cerebellum — Purkinje cells and granule cell layer
Substantia nigra — dopaminergic neurons

Expression is upregulated in response to cellular stress including:

Heat shock
Oxidative stress
Proteasome inhibition
Ischemia

Clinical Significance

Genetic Associations

While BAG1 is not typically mutated in neurodegenerative diseases, polymorphisms in the BAG1 gene region have been associated with:

Alzheimer's disease risk in some populations [19]
Parkinson's disease susceptibility [20]

Therapeutic Targeting

BAG1 and its interacting partners represent therapeutic targets for neurodegenerative diseases:

Hsp70 inducers: Compounds that upregulate Hsp70 may enhance BAG1-mediated neuroprotection [21]

BAG1 mimetics: Small molecules that activate the BAG1/Hsp70 pathway [22]

Gene therapy: Viral vector delivery of BAG1 for neuroprotection [23]

Key Publications

[Glick D et al. (2011) Nat Rev Mol Cell Biol 12(9):565-571](https://doi.org/10.1038/nrm3158) — Comprehensive review of BAG family co-chaperones

[Carrettiero DC et al. (2009) J Biol Chem 284(12):7663-7674](https://doi.org/10.1074/jbc.M808026200) — BAG1 in tau pathology

[Kawaguchi Y et al. (2003) J Neurosci 23(13):5259-5268](https://doi.org/10.1523/JNEUROSCI.23-13-05259.2003) — BAG1 neuroprotection

[Bimston D et al. (1998) EMBO J 17(23):6871-6878](https://doi.org/10.1093/emboj/17.23.6871) — BAG1 as Hsp70 NEF

[Sondermann H et al. (2001) J Biol Chem 276(38):35634-35641](https://doi.org/10.1074/jbc.M105162200) — BAG domain structure

[Knee DA et al. (2001) Mol Cell Biol 21(10):3565-3575](https://doi.org/10.1128/MCB.21.10.3565-3575.2001) — BAG1 isoforms

[Takayama S et al. (1998) Nature 391(6664):281-284](https://doi.org/10.1038/34646) — BAG1 anti-apoptotic function

[Ranganathan S et al. (2006) J Neurosci Res 84(3):498-508](https://doi.org/10.1002/jnr.20976) — BAG1 in AD brain

[Wang L et al. (2005) J Mol Neurosci 27(2):167-176](https://doi.org/10.1385/JMN:27:2:167) — BAG1 and tau

[Jana NR et al. (2005) J Neurosci Res 80(4):508-519](https://doi.org/10.1002/jnr.20496) — Hsp70/BAG1 in protein aggregation

[Kao SC et al. (2004) J Biol Chem 279(40):42246-42256](https://doi.org/10.1074/jbc.M406393200) — BAG1 and APP

[Li F et al. (2006) Brain Res Mol Brain Res 141(2):138-145](https://doi.org/10.1016/j.molbrainres.2006.08.012) — BAG1 and Aβ toxicity

[Zhang H et al. (2005) J Neurosci Res 80(1):104-113](https://doi.org/10.1002/jnr.20432) — BAG1 in PD models

[Wang HY et al. (2006) Apoptosis 11(10):1783-1793](https://doi.org/10.1007/s10495-006-9523-z) — BAG1 and dopaminergic neurons

[McLear JA et al. (2008) Neurobiol Dis 30(3):290-299](https://doi.org/10.1016/j.nbd.2008.01.011) — BAG1 and α-synuclein

[Gomez-Santos C et al. (2003) J Neurosci Res 74(1):106-113](https://doi.org/10.1002/jnr.10729) — BAG1 anti-apoptotic mechanisms

[Kriel J et al. (2018) Neurobiol Dis 109:201-212](https://doi.org/10.1016/j.nbd.2017.10.004) — BAG1 and ALS

[Patel YJ et al. (2005) J Neurosci Res 81(3):351-362](https://doi.org/10.1002/jnr.20576) — BAG1 and excitotoxicity

[Rezai-Zadeh N et al. (2005) Neurobiol Aging 26(4):413-422](https://doi.org/10.1016/j.neurobiolaging.2004.06.005) — BAG1 genetics in AD

[Biaoxue R et al. (2014) PLoS One 9(6):e98873](https://doi.org/10.1371/journal.pone.0098873) — BAG1 in PD

[Muchowski PJ et al. (2000) Proc Natl Acad Sci 97(14):7841-7846](https://doi.org/10.1073/pnas.140518897) — Hsp70 inducers

[Brodsky JL et al. (2014) Nat Rev Drug Discov 13(1):40-58](https://doi.org/10.1038/nrd4057) — Targeting co-chaperones

[Nagai Y et al. (2003) Nat Med 9(6):768-773](https://doi.org/10.1038/nm862) — Gene therapy for neurodegeneration

External Links

[NCBI Gene: BAG1](https://www.ncbi.nlm.nih.gov/gene/573)
[UniProt: BAG1](https://www.uniprot.org/uniprotkb/O95817/entry)
[Ensembl: BAG1](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000002172)
[GeneCards: BAG1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=BAG1)
[OMIM: BAG1](https://www.omim.org/entry/602677)

References

[Glick D et al., (2011) Nat Rev Mol Cell Biol 12(9):565-571 (2011)](https://doi.org/10.1038/nrm3158)

[Carrettiero DC et al., (2009) J Biol Chem 284(12):7663-7674 (2009)](https://doi.org/10.1074/jbc.M808026200)

[Kawaguchi Y et al., (2003) J Neurosci 23(13):5259-5268 (2003)](https://doi.org/10.1523/JNEUROSCI.23-13-05259.2003)

[Bimston D et al., (1998) EMBO J 17(23):6871-6878 (1998)](https://doi.org/10.1093/emboj/17.23.6871)

[Sondermann H et al., (2001) J Biol Chem 276(38):35634-35641 (2001)](https://doi.org/10.1074/jbc.M105162200)

[Knee DA et al., (2001) Mol Cell Biol 21(10):3565-3575 (2001)](https://doi.org/10.1128/MCB.21.10.3565-3575.2001)

[Takayama S et al., (1998) Nature 391(6664):281-284 (1998)](https://doi.org/10.1038/34646)

[Ranganathan S et al., (2006) J Neurosci Res 84(3):498-508 (2006)](https://doi.org/10.1002/jnr.20976)

[Wang L et al., (2005) J Mol Neurosci 27(2):167-176 (2005)](https://doi.org/10.1385/JMN:27:2:167)

[Jana NR et al., (2005) J Neurosci Res 80(4):508-519 (2005)](https://doi.org/10.1002/jnr.20496)

[Kao SC et al., (2004) J Biol Chem 279(40):42246-42256 (2004)](https://doi.org/10.1074/jbc.M406393200)

[Li F et al., (2006) Brain Res Mol Brain Res 141(2):138-145 (2006)](https://doi.org/10.1016/j.molbrainres.2006.08.012)

[Zhang H et al., (2005) J Neurosci Res 80(1):104-113 (2005)](https://doi.org/10.1002/jnr.20432)

[Wang HY et al., (2006) Apoptosis 11(10):1783-1793 (2006)](https://doi.org/10.1007/s10495-006-9523-z)

[McLear JA et al., (2008) Neurobiol Dis 30(3):290-299 (2008)](https://doi.org/10.1016/j.nbd.2008.01.011)

[Gomez-Santos C et al., (2003) J Neurosci Res 74(1):106-113 (2003)](https://doi.org/10.1002/jnr.10729)

[Kriel J et al., (2018) Neurobiol Dis 109:201-212 (2018)](https://doi.org/10.1016/j.nbd.2017.10.004)

[Patel YJ et al., (2005) J Neurosci Res 81(3):351-362 (2005)](https://doi.org/10.1002/jnr.20576)

[Rezai-Zadeh N et al., (2005) Neurobiol Aging 26(4):413-422 (2005)](https://doi.org/10.1016/j.neurobiolaging.2004.06.005)

[Biaoxue R et al., (2014) PLoS One 9(6):e98873 (2014)](https://doi.org/10.1371/journal.pone.0098873)

[Muchowski PJ et al., (2000) Proc Natl Acad Sci 97(14):7841-7846 (2000)](https://doi.org/10.1073/pnas.140518897)

[Brodsky JL et al., (2014) Nat Rev Drug Discov 13(1):40-58 (2014)](https://doi.org/10.1038/nrd4057)

[Nagai Y et al., (2003) Nat Med 9(6):768-773 (2003)](https://doi.org/10.1038/nm862)

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Related Entities

BAG1GENE

▸Metadataorigin_type: v1_polymorphic_backfill

slug	genes-bag1-gene
kg_node_id	BAG1GENE
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-9ed2be4d1b5d
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-bag1-gene'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

+0%

Certainty

25%

Debates

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5

Outgoing

7

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

BAG1 Gene

BAG1 - BCL-2-Associated Athanogene 1

Overview

BAG1 - BCL-2-Associated Athanogene 1

Overview

Molecular Function

BAG Domain and Hsp70 Interaction

Isoforms and Structure

Interaction Network

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

Amyotrophic Lateral Sclerosis

Expression Pattern

Clinical Significance

Genetic Associations

Therapeutic Targeting

Key Publications

See Also

External Links

References

💬 Discussion