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| Full Name | STIP1 Homology And U-Box Containing Protein 1 |
| Chromosome | 16p13.3 |
| NCBI Gene ID | 10273 |
| Ensembl ID | ENSG00000120539 |
| OMIM ID | 607207 |
| UniProt ID | Q9UNE7 |
| Associated Diseases | ALS, Parkinson's Disease, Spinocerebellar Ataxia, Hereditary Spastic Paraplegia |
¶ STUB1 — CHIP (STIP1 Homology And U-Box Containing Protein 1)
Stub1 — Chip is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
STUB1 (also known as CHIP - C-terminus of HSC70-Interacting Protein) encodes a ubiquitin ligase and cochaperone that plays critical roles in protein quality control. It acts at the interface between chaperone-mediated folding and ubiquitin-proteasome degradation.
CHIP (STUB1) is a multifunctional protein that bridges the chaperone and ubiquitin-proteasome systems. Its primary functions include:
- E3 ubiquitin ligase: Catalyzing the transfer of ubiquitin to substrate proteins
- U-box domain: Mediating interaction with E2 ubiquitin-conjugating enzymes
- Chaperone clients: Targeting misfolded chaperone clients for degradation
- HSP70/HSP90 interaction: Binding to heat shock proteins via TPR domain
- Folding vs. degradation decision: Determining whether proteins are refolded or degraded
- Protein triage: Deciding the fate of damaged proteins
- Heat shock response: Regulating HSF1 and heat shock gene expression
- Oxidative stress: Protecting against oxidative damage
- ER stress: Participating in ER-associated degradation
- Protein quality control: Clearing aggregated proteins in neurons
- Synaptic maintenance: Supporting synaptic protein turnover
- Neuroprotection: Protecting neurons from proteotoxic stress
CHIP is involved in ALS pathogenesis:
- SOD1 degradation: Promoting clearance of mutant SOD1
- TDP-43 regulation: Targeting TDP-43 aggregates
- Neuroprotection: Reducing motor neuron stress
Mutations and reduced CHIP function have been observed in ALS patients.
CHIP has protective roles in PD:
- Alpha-synuclein clearance: Promoting degradation of toxic alpha-synuclein
- Parkin interaction: Working with Parkin in mitophagy
- Dopaminergic neuron protection: Preserving dopaminergic neurons
STUB1 mutations cause spinocerebellar ataxia type 16 (SCA16):
- Cerebellar degeneration: Progressive ataxia
- Cognitive involvement: Variable cognitive decline
- Autosomal recessive inheritance: Biallelic mutations
Mutations in STUB1 cause Gordon Holmes syndrome:
- Hypogonadotropic hypogonadism: Reproductive dysfunction
- Ataxia: Progressive cerebellar ataxia
- Dementia: Cognitive decline
- Protein aggregation: Impaired clearance of misfolded proteins
- Chaperone dysfunction: Disrupted HSP70/HSP90 activity
- Ubiquitination defects: Reduced protein ubiquitination
- Mitochondrial dysfunction: Secondary effects on mitochondria
CHIP is ubiquitously expressed with high levels in:
- Brain (neurons)
- Skeletal muscle
- Heart
- Testis
Within the nervous system:
- Purkinje cells
- Motor neurons
- Hippocampal neurons
- Shi CH, et al. "CHIP mutations cause Gordon Holmes syndrome." Brain 2013. DOI:10.1093/brain/awt268
- Tashiro Y, et al. "CHIP promotes degradation of excess Pael-R." Neuron 2004.
The study of Stub1 — Chip 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.
- Shi CH, et al. STUB1 mutations in Gordon Holmes syndrome. Brain 2013.
- Tashiro Y, et al. CHIP function in neurodegeneration. Neuron 2004.