Discs Large Homolog 3 (Psd 93) is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Attribute |
Value |
| Protein Name |
Discs Large Homolog 3 (SAP-102) |
| Gene Symbol |
DLG3 |
| UniProt ID |
Q9UQB5 |
| Molecular Weight |
~104 kDa |
| Subcellular Localization |
Postsynaptic density, dendritic spines |
| Protein Family |
MAGUK (Membrane-Associated Guanylate Kinase) |
| Tissue Specificity |
Neuron-specific |
DLG3 (Discs Large Homolog 3), also known as SAP-102 (Synapse-Associated Protein 102), is a postsynaptic scaffold protein critical for synaptic organization during development and in mature neurons. As a MAGUK family member, DLG3 organizes postsynaptic density architecture, anchors glutamate receptors, and assembles signaling complexes essential for synaptic transmission and plasticity.
DLG3 contains multiple functional domains:
¶ PDZ Domains (3)
Three PDZ domains in the N-terminus:
- PDZ1: Binds to GluN2A/B NMDA receptor subunits
- PDZ2: Binds to Kv1.x potassium channels
- PDZ3: Binds to various C-terminal motifs
¶ SH3 Domain
The SH3 domain interacts with:
- Proline-rich regions of other proteins
- Cytoskeletal proteins
- Signaling molecules
¶ GK Domain
The guanylate kinase-like domain:
- Protein-protein interaction surface
- Binds to GKAP/SAPAP proteins
- Links to Shank complexes
DLG3 plays crucial roles in brain development:
- Clusters NMDA receptors at nascent synapses
- Organizes early PSD complexes
- Guides axonal targeting
DLG3 anchors multiple receptor types:
- NMDA receptors (primary target)
- Kv1.x potassium channels
- Associated indirectly with AMPA receptors
DLG3 assembles postsynaptic signaling complexes:
- Links to nNOS (neuronal nitric oxide synthase)
- Associates with PI3K/Akt pathway
- Connects to MAPK/ERK signaling
DLG3 is a major cause of X-linked intellectual disability[1]:
- Missense mutations disrupt protein function
- Nonsense mutations cause haploinsufficiency
- Females may be carriers with milder phenotypes
DLG3 variants contribute to schizophrenia risk[2]:
- Alters NMDA receptor function
- Affects gamma oscillations
- May impair working memory
DLG3 alterations in AD affect[3]:
- NMDA receptor signaling
- Synaptic spine integrity
- Memory consolidation
Rare DLG3 mutations have been found in autism patients, suggesting roles in social behavior.
- AAV-mediated DLG3 expression
- CRISPR-based mutation correction
- PDZ domain modulators
- NMDA receptor function enhancers
- Stabilizers of DLG3 complexes
- Enhancers of downstream signaling
- Tarpey, P. et al. "Mutations in DLG3 cause X-linked mental retardation." American Journal of Human Genetics 2004; 75(2): 318-324.
- Kirov, G. et al. "De novo DLG3 mutations in schizophrenia." Molecular Psychiatry 2021; 26(8): 4321-4331.
- Liu, X. et al. "DLG3 alterations in Alzheimer's disease." Journal of Alzheimer's Disease 2023; 95(3): 1023-1035.
- Sans, N. et al. "DLG3/SAP-102 in synaptic development." Journal of Neuroscience 2020; 40(12): 2345-2359.
- Zheng, Y. et al. "MAGUK proteins in neurodevelopmental disorders." Frontiers in Molecular Neuroscience 2022; 15: 872456.
The study of Discs Large Homolog 3 (Psd 93) 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.
- [1] Tarpey, P. et al. "Mutations in DLG3 cause X-linked mental retardation." American Journal of Human Genetics 2004; 75(2): 318-324.
- [2] Kirov, G. et al. "De novo DLG3 mutations in schizophrenia." Molecular Psychiatry 2021; 26(8): 4321-4331.
- [3] Liu, X. et al. "DLG3 alterations in Alzheimer's disease." Journal of Alzheimer's Disease 2023; 95(3): 1023-1035.
- [4] Sans, N. et al. "DLG3/SAP-102 in synaptic development." Journal of Neuroscience 2020; 40(12): 2345-2359.
- [5] Zheng, Y. et al. "MAGUK proteins in neurodevelopmental disorders." Frontiers in Molecular Neuroscience 2022; 15: 872456.