| Protein Name |
Connexin 32 (Cx32, GJB1) |
| Gene |
GJB1 |
| UniProt |
P29508 |
| Molecular Weight |
~32 kDa |
| Subcellular Localization |
Plasma membrane, gap junctions |
| Protein Family |
Connexin family |
| Structure |
Four transmembrane domains, two extracellular loops, cytoplasmic N- and C-termini |
Gjb1 Protein — Connexin 32 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Connexin 32 (Cx32), also known as GJB1, is a 32-kDa gap junction protein encoded by the GJB1 gene. It is expressed in Schwann cells of the peripheral nervous system, where it forms gap junctions that enable direct cell-to-cell communication. Mutations in GJB1 cause X-linked Charcot-Marie-Tooth disease (CMTX), making this protein a key therapeutic target for peripheral neuropathy.
Cx32 is a member of the connexin family with distinctive structural features:
- Four Transmembrane Domains: Alpha-helical segments spanning the membrane
- Two Extracellular Loops: Mediate docking with adjacent cell gap junctions
- Cytoplasmic Loops: N-terminal and C-terminal domains in the cytoplasm
- Molecular weight: Approximately 32 kDa
- Six subunits: Forms hexameric hemichannels (connexons)
The protein assembles into hexameric hemichannels, which dock with hemichannels from adjacent cells to form gap junction channels.
- Cell-to-Cell Coupling: Forms gap junctions between adjacent Schwann cells
- Ionic Current Flow: Allows passage of ions and small molecules (<1 kDa)
- Metabolic Cooperation: Enables sharing of metabolites between cells
- Signal Propagation: Mediates electrical and chemical signaling
- Schwann Cell Networks: Creates functional syncytia of Schwann cells
- Node of Ranvier Organization: Critical for proper nodal structure
- Myelin Maintenance: Supports ongoing myelin sheath integrity
- Axonal Support: Provides metabolic support to underlying axons
Cx32 interacts with:
- Other Connexins: Can form heteromeric channels with Cx29, Cx46
- Cytoskeletal Proteins: Interactions with scaffolding proteins
- Signaling Molecules: Second messenger passage through channels
Over 400 GJB1 mutations cause CMTX with variable phenotypes:
- Gap Junction Dysfunction: Impaired intercellular communication
- Schwann Cell Isolation: Loss of metabolic coupling
- Myelin Abnormalities: Progressive demyelination
- Axonal Degeneration: Secondary to demyelination
- Dominant-negative Effects: Mutant proteins disrupt wild-type function
- Protein Misfolding: Many mutations cause ER retention
- Loss of Channel Function: Impaired permeability
- Reduced Expression: Some mutations reduce protein levels
- Gene Replacement: AAV-mediated delivery of functional GJB1
- Gene Editing: CRISPR approaches to correct mutations
- Targeted Expression: Schwann cell-specific promoters
- Channel Openers: Small molecules to enhance gap junction function
- Targeted Delivery: CNS/PNS-specific approaches
- Peptide-based Modulators: Mimetics of extracellular domains
- Chaperones: ER chaperone enhancement for misfolded proteins
- Protein Stabilizers: Small molecules to improve mutant protein function
- Replacement Therapy: Exogenous protein delivery (challenging)
- Connexin 32 mutations and Charcot-Marie-Tooth disease. Brain, 2018.
- Gap junction function in peripheral neuropathy. Experimental Neurology, 2020.
- Structure of connexin 32 gap junction channels. PNAS, 2014.
- CMTX: therapeutic strategies and challenges. Journal of the Peripheral Nervous System, 2020.
The study of Gjb1 Protein — Connexin 32 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.
- Connexin 32 mutations and Charcot-Marie-Tooth disease. Brain, 2018. DOI
- Gap junction function in peripheral neuropathy. Experimental Neurology, 2020. DOI
- Structure of connexin 32 gap junction channels. PNAS, 2014. DOI
- CMTX: therapeutic strategies and challenges. Journal of the Peripheral Nervous System, 2020. DOI
- UniProt: P29508
Page auto-generated from NeuroWiki protein database. Last updated: 2026-03-05.