RAB7 Gene

RAB7 — Member RAS Oncogene Family

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">RAB7 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>RAB7</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>RAB7, member RAS oncogene family</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>3q21.3</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[7409](https://www.ncbi.nlm.nih.gov/gene/7409)</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>[602298](https://omim.org/entry/602298)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>[ENSG00000075711](https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000075711)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[P51149](https://www.uniprot.org/uniprot/P51149)</td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>Small GTPase (Rab family)</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td>Charcot-Marie-Tooth disease type 2B, Alzheimer's disease, Parkinson's disease, Huntington's disease</td>
</tr>
</table>

Introduction

RAB7 — Member RAS Oncogene Family

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">RAB7 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>RAB7</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>RAB7, member RAS oncogene family</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>3q21.3</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[7409](https://www.ncbi.nlm.nih.gov/gene/7409)</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>[602298](https://omim.org/entry/602298)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>[ENSG00000075711](https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000075711)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[P51149](https://www.uniprot.org/uniprot/P51149)</td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>Small GTPase (Rab family)</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td>Charcot-Marie-Tooth disease type 2B, Alzheimer's disease, Parkinson's disease, Huntington's disease</td>
</tr>
</table>

Introduction

The RAB7 gene (RAB7, member RAS oncogene family) encodes a member of the RAB family of small GTPases that is essential for endolysosomal trafficking, autophagosome maturation, and lysosomal function. As a key regulator of the late endocytic pathway, RAB7 coordinates membrane fusion events that are critical for cellular homeostasis, nutrient recycling, and protein quality control. In neurons, where intracellular transport over long distances is essential for synaptic function, RAB7 plays a particularly vital role in maintaining axonal and dendritic integrity.

RAB7 has emerged as a critical player in neurodegenerative disease pathogenesis. Mutations in RAB7 cause Charcot-Marie-Tooth disease type 2B (CMT2B), an autosomal dominant peripheral neuropathy characterized by distal muscle weakness and sensory loss. Additionally, RAB7 dysfunction has been implicated in Alzheimer's disease, Parkinson's disease, and Huntington's disease, where defects in autophagic flux and lysosomal function contribute to protein aggregate accumulation and neuronal death.

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Gene Structure and Protein

The human RAB7 gene spans approximately 11 kb and consists of 7 exons encoding a 207-amino acid protein with a molecular weight of approximately 23 kDa. Like other Rab GTPases, RAB7 contains conserved GTP-binding motifs (GxxxxGKST, DxxG, and NKXD) that enable cyclic GDP/GTP binding and hydrolysis. The protein undergoes post-translational geranylgeranylation at C-terminal cysteine residues, which facilitates membrane association.

RAB7 cycles between an active GTP-bound state and an inactive GDP-bound state, regulated by:

• GTPase-activating proteins (GAPs): Accelerate GTP hydrolysis (e.g., TBC1D5, TBC1D15)
• Guanine nucleotide exchange factors (GEFs): Promote GTP loading (e.g., Mon1-Ccz1 complex)
• GDP dissociation inhibitors (GDIs): Extract GDP-bound RAB7 from membranes for recycling

Cellular Functions

Endosomal Trafficking

RAB7 is the master regulator of the late endocytic pathway. It controls:

Autophagy and Autophagosome Maturation

RAB7 plays multiple critical roles in autophagy:

• Autophagosome formation: RAB7 is recruited to isolation membranes during autophagosome biogenesis
• Autophagosome-lysosome fusion: RAB7 on autophagosomes interacts with lysosomal tethering complexes (HOPS, CORVET) to mediate fusion [@rab7_autophagy]
• Effector recruitment: NRBF2 is a RAB7 effector required for autophagosome maturation, linking RAB7 to the PI3K-III complex [@nrbf2_rab7]

Lysosomal Function and Biogenesis

RAB7 is essential for lysosome maintenance:

• Lysosome positioning: RAB7-dependent motility positions lysosomes throughout the cytoplasm
• Lysosomal acidifiction: RAB7 regulates v-ATPase recruitment to lysosomes
• Lysosome biogenesis: RAB7 coordinates the delivery of lysosomal hydrolases from the Golgi apparatus [@rab7_lysosome_biogenesis]

Mitochondrial Quality Control

RAB7 participates in mitochondrial dynamics and quality control:

• Mitophagy initiation: RAB7 is recruited to damaged mitochondria during parkin-dependent mitophagy
• Mitochondrial trafficking: RAB7 controls mitochondrial transport in axons
• Mitochondrial-lysosomal contact sites: RAB7 facilitates mitochondrial fission and turnover [@rab7_mitochondria]

Expression Pattern

RAB7 is ubiquitously expressed with particularly high levels in the nervous system:

• Brain regions: Substantia nigra, hippocampus (CA1 and dentate gyrus), cerebral cortex (layers II-IV), cerebellum (Purkinje cells), and spinal cord motor neurons
• Cell types: All neuronal subtypes (pyramidal neurons, interneurons, dopaminergic neurons), astrocytes, microglia, and oligodendrocytes
• Subcellular localization: Cytoplasmic, associated with late endosomes, lysosomes, autophagosomes, and mitochondria

Disease Associations

Charcot-Marie-Tooth Disease Type 2B (CMT2B)

CMT2B (OMIM #600882) is an autosomal dominant axonal peripheral neuropathy caused by RAB7 mutations. The disease is characterized by:

• Onset: Typically adolescence to early adulthood
• Symptoms: Distal muscle weakness and atrophy, sensory loss, foot deformities (pes cavus, hammertoes), and slowed nerve conduction velocities
• Genetics: Heterozygous missense mutations in RAB7 (most commonly p.L129F, p.K157N, p.V162M)

Alzheimer's Disease

RAB7 dysfunction contributes to AD pathogenesis through multiple mechanisms:

• Amyloid processing: RAB7 regulates APP trafficking and amyloid-beta secretion
• Autophagic-lysosomal dysfunction: RAB7 impairment leads to accumulation of autophagic vacuoles containing amyloid and tau aggregates
• Lysosomal membrane permeabilization: RAB7 deficiency causes lysosomal leakage and caspase activation
• Synaptic decline: RAB7 loss disrupts synaptic vesicle trafficking and BDNF delivery [@rab7_alzheimer]

Parkinson's Disease

RAB7 is implicated in PD through:

• Alpha-synuclein clearance: RAB7-dependent autophagy is essential for clearing pathogenic alpha-synuclein species
• Lysosomal function: PD-associated genes (GBA, ATP13A2, LRRK2) converge on RAB7-mediated lysosomal pathways
• Mitochondrial quality control: RAB7 dysfunction impairs mitophagy of damaged mitochondria
• Dopaminergic neuron vulnerability: RAB7 is highly expressed in substantia nigra dopamine neurons [@rab7_parkinson]

Huntington's Disease

RAB7 dysfunction contributes to HD pathogenesis:

• Huntingtin trafficking: Mutant huntingtin disrupts RAB7-dependent vesicular transport
• Autophagy impairment: RAB7-mediated autophagosome-lysosome fusion is compromised
• Aggregate clearance: RAB7 deficiency leads to accumulation of mutant huntingtin aggregates
• Neuronal integrity: Axonal transport defects compound neurodegeneration [@rab7_huntington]

Therapeutic Implications

RAB7 represents a promising therapeutic target:

Key Publications

See Also

• [RAB proteins in neurodegeneration](/mechanisms/rab-protein-pathway)
• [Endosomal trafficking in Parkinson's disease](/mechanisms/endosomal-trafficking-pd)
• [Autophagy and neurodegeneration](/mechanisms/autophagy-lysosome-neurodegeneration)
• [Charcot-Marie-Tooth disease](/diseases/charcot-marie-tooth-disease)
• [Lysosomal storage disorders and neurodegeneration](/mechanisms/lysosomal-dysfunction)
• [Alpha-synuclein](/proteins/alpha-synuclein)
• [LRRK2](/genes/lrrk2)
• [GBA](/genes/gba)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving RAB7 Gene discovered through SciDEX knowledge graph analysis: