RAC2 — RAS-Related C3 Botulinum Toxin Substrate 2

RAC2 — RAS-Related C3 Botulinum Toxin Substrate 2

| Gene Symbol | RAC2 | [@huang2020]
|---|---|
| Full Name | RAS-Related C3 Botulinum Toxin Substrate 2 |
| Chromosomal Location | 22q13.1 |
| NCBI Gene ID | [5879](https://www.ncbi.nlm.nih.gov/gene/5879) |
| OMIM | [602049](https://www.omim.org/entry/602049) |
| Ensembl ID | ENSG00000128340 |
| UniProt ID | [P15153](https://www.uniprot.org/uniprot/P15153) |
| Associated Diseases | Neutrophil Immunodeficiency Syndrome, Parkinson's Disease, Alzheimer's Disease |

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Overview

RAC2 — RAS-Related C3 Botulinum Toxin Substrate 2

| Gene Symbol | RAC2 | [@huang2020]
|---|---|
| Full Name | RAS-Related C3 Botulinum Toxin Substrate 2 |
| Chromosomal Location | 22q13.1 |
| NCBI Gene ID | [5879](https://www.ncbi.nlm.nih.gov/gene/5879) |
| OMIM | [602049](https://www.omim.org/entry/602049) |
| Ensembl ID | ENSG00000128340 |
| UniProt ID | [P15153](https://www.uniprot.org/uniprot/P15153) |
| Associated Diseases | Neutrophil Immunodeficiency Syndrome, Parkinson's Disease, Alzheimer's Disease |

</div>

Overview

RAS-Related C3 Botulinum Toxin Substrate 2 (RAC2) is a small GTPase belonging to the Rho family of GTP-binding proteins. Like other Rho GTPases, RAC2 cycles between an active GTP-bound state and an inactive GDP-bound state, functioning as a molecular switch that regulates diverse cellular processes.[@bosco2020] RAC2 is highly expressed in hematopoietic cells but also has significant expression in the nervous system, particularly in [neurons](/entities/neurons) and [microglia](/cell-types/microglia-neuroinflammation). It plays essential roles in actin cytoskeleton dynamics, synaptic plasticity, and immune cell function.[@huang2021]

In the brain, RAC2 is critically involved in regulating dendritic spine morphology and synaptic function. Through its effects on the actin cytoskeleton via the WASF (Wiskott-Aldrich syndrome protein family) complex, RAC2 influences filopodia and lamellipodia formation, which are fundamental to synaptic structure and plasticity.[@huang2021] Additionally, RAC2 regulates microglial chemotaxis and phagocytosis, linking it to neuroinflammatory processes in neurodegenerative diseases.[@marei2021] Dysregulated RAC2 signaling has been implicated in both Alzheimer's disease (AD) and Parkinson's disease (PD), where it contributes to synaptic deficits and chronic neuroinflammation.[@zhang2019][@huang2020]

Function

RAC2 is a small GTPase belonging to the Rho family. It cycles between active (GTP-bound) and inactive (GDP-bound) states, acting as a molecular switch for various cellular processes.

Structure

• ~192 amino acids in length
• GTPase domain: Binds GTP/GDP and has intrinsic GTPase activity
• Effector region: Interacts with downstream targets
• Isoprenylation site: For membrane localization

Normal Function in the Nervous System

Actin Cytoskeleton

• Filopodia formation: Through WASF complex
• Lamellipodia: Membrane ruffling and cell motility
• Dendritic spine morphology: Regulates synaptic structure

Synaptic Function

• Postsynaptic density: Regulates spine density and shape
• Synaptic plasticity: Involved in [LTP](/mechanisms/long-term-potentiation) and LTD
• [NMDA receptor](/entities/nmda-receptor) trafficking: Modulates receptor localization

Microglial Function

• Chemotaxis and migration
• Phagocytosis
• [ROS](/entities/reactive-oxygen-species) production through NADPH oxidase activation

Disease Associations

Parkinson's Disease

• RAC2 dysregulation in PD substantia nigra
• Contributes to:
• Microglial migration dysfunction
• Altered phagocytosis
• Neuroinflammation[@zhang2019]

Alzheimer's Disease

• Altered RAC2 signaling in AD brain
• Links to:
• Actin cytoskeleton dysfunction
• Synaptic spine abnormalities
• Microglial pathology[@huang2020]

Neutrophil Immunodeficiency Syndrome

• Rare immunodeficiency caused by RAC2 mutations
• Defective neutrophil chemotaxis

Expression

Brain Expression

• Neurons: High expression, especially in [cortex](/brain-regions/cortex) and [hippocampus](/brain-regions/hippocampus)
• Microglia: Moderate expression
• [Astrocytes](/entities/astrocytes): Lower expression

Therapeutic Targeting

Inhibitors

• EHT 1864: RAC2-specific inhibitor
• NSC23766: RAC1/2 inhibitor

Research Status

• RAC2 as target is emerging area
• Must balance neuronal vs. microglial effects[@marei2021]

See Also

• [RAC2 Protein](/proteins/rac2-protein)
• [Rho GTPases](/mechanisms/rho-gtpases)
• [Actin Cytoskeleton](/mechanisms/actin-cytoskeleton)
• [Synaptic Plasticity](/mechanisms/synaptic-plasticity)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [RAC1](/genes/rac1)
• [CDC42](/genes/cdc42)

External Links

• [NCBI Gene: RAC2](https://www.ncbi.nlm.nih.gov/gene/5879)
• [UniProt: P15153](https://www.uniprot.org/uniprot/P15153)
• [OMIM: 602049](https://www.omim.org/entry/602049)
• [Ensembl: ENSG00000128340](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000128340)
• [GeneCards: RAC2](https://www.genecards.org/cgi-bin/carddisp.pl?gene=RAC2)

Brain Atlas Resources

• [Allen Human Brain Atlas — RAC2 Expression](https://human.brain-map.org/microarray/search/show?search_term=RAC2): Gene expression data in human brain
• [Allen Mouse Brain Atlas — RAC2](https://mouse.brain-map.org/search/show?search_term=RAC2): Mouse brain expression data
• [BrainSpan — RAC2 Developmental Transcriptome](https://brainspan.org/lair/list?gene=RAC2): Developmental expression data

References

Pathway Diagram

The following diagram shows the key molecular relationships involving RAC2 — RAS-Related C3 Botulinum Toxin Substrate 2 discovered through SciDEX knowledge graph analysis: