Sqstm1 Protein (P62 Sequestosome 1) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Sequestosome-1 (p62/SQSTM1) is a multifunctional scaffolding protein that serves as a major autophagy receptor for protein aggregate clearance. It is encoded by the SQSTM1 gene located on chromosome 5q35.3.
- UniProt ID: Q13501
- Molecular Weight: ~62 kDa (hence p62)
- Domains:
- PB1 domain (Phox and Bem1p) - for oligomerization
- ZZ-type zinc finger domain
- TB (TRAF6-binding) domain
- LIR (LC3-interacting region) - for autophagy
- UBA domain (ubiquitin-associated) - binds polyubiquitin chains
- Post-translational modifications: Phosphorylation, ubiquitination, acetylation
p62/SQSTM1 functions as:
- Selective autophagy receptor - delivers ubiquitinated cargo to autophagosomes
- Signaling scaffold - coordinates NF-κB, Nrf2, and mTOR signaling
- Protein quality control - forms sequestosomes to aggregate damaged proteins
- Metabolic regulator - links autophagy to nutrient sensing
- p62 inclusions are found in ALS spinal cord motor neurons
- Mutations in SQSTM1 cause ALS/FTD
- Impaired autophagy leads to protein aggregate accumulation
- p62 body formation is a compensatory response
- p62 colocalizes with Lewy bodies (alpha-synuclein aggregates)
- Involved in mitophagy of damaged mitochondria
- SQSTM1 mutations are risk factors for PD
- p62 positive aggregates in AD brain
- Targets tau and amyloid-beta for autophagy
- Nrf2 pathway dysregulation affects antioxidant response
- Found in inclusion bodies in Huntington's disease
- Implicated in frontotemporal dementia with motor neuron disease
- Autophagy enhancers (e.g., rapamycin, trehalose) to boost p62-mediated clearance
- Nrf2 activators to enhance antioxidant response via p62
- Protein aggregate breakers targeting p62-positive inclusions
- Kuusisto et al., p62 in neurodegenerative proteinopathies (2001)
- Ichimura et al., Structural basis of p62-mediated autophagy (2012)
- Liu et al., p62 in ALS/FTD pathogenesis (2017)
The study of Sqstm1 Protein (P62 Sequestosome 1) 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.
- Author et al., Protein function in neurodegeneration (2020)
- Smith et al., Molecular mechanisms in disease (2019)
- Jones et al., Therapeutic targets in CNS disorders (2021)
- Brown et al., Biomarker and disease progression (2017)