RAPSN (Receptor-Associated Protein of the Synapse)
Key postsynaptic scaffold protein at the neuromuscular junction; mutations cause congenital myasthenic syndromes.
Gene Information Card
| Symbol | RAPSN |
|---|---|
| Full Name | Receptor-Associated Protein of the Synapse |
| Gene Type | protein-coding |
| Chromosomal Location | 11p11.2 |
| NCBI Gene ID | 5913 ncbi.nlm.nih.gov/gene/5913 |
| Ensembl ID | ENSG00000165916 |
| UniProt ID | Q13702 |
| OMIM ID | 601592 |
| HGNC ID | 9855 |
| Aliases | RAPSN, RAPSYN, CMS11, CMS1D, FADS, RAPSNP |
Description
RAPSN encodes rapsyn, a 43-kDa postsynaptic scaffold protein essential for clustering and anchoring nicotinic acetylcholine receptors (AChRs) at the neuromuscular junction (NMJ). Rapsyn interacts directly with AChR subunits and links them to the cytoskeleton via dystrophin-associated glycoproteins. Loss-of-function mutations in RAPSN cause congenital myasthenic syndromes (CMS), characterized by fatigable muscle weakness. RAPSN is also implicated in certain cancers through altered expression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Congenital Myasthenic Syndrome 1D (CMS1D) | Loss-of-function mutations impair AChR clustering at the NMJ, reducing synaptic transmission. | ClinVar, OMIM |
| Congenital Myasthenic Syndrome 11 (CMS11) | Similar mechanism; recessive mutations in RAPSN lead to postsynaptic AChR deficiency. | ClinVar, OMIM |
| Myasthenia Gravis (autoimmune) | Rapsyn is a target of autoantibodies in some seronegative MG patients. | PubMed, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skeletal Muscle | 12.5 | High |
| Cerebellum | 1.2 | Low |
| Heart | 0.8 | Low |
| Liver | 0.1 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| RH-30 (rhabdomyosarcoma) | 8.3 | High expression |
| SH-SY5Y (neuroblastoma) | 2.1 | Moderate |
| HeLa (cervical carcinoma) | 0.5 | Low |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.264C>A (p.Asn88Lys) | Missense | Common in CMS | Reduced AChR clustering |
| c.1177C>T (p.Arg393Cys) | Missense | Rare | Impaired rapsyn-AChR interaction |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss of protein expression |
Mutation functional classification
Loss of Function (LOF)
Most RAPSN CMS mutations are loss-of-function, reducing rapsyn expression or AChR clustering ability.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
Some missense mutations (e.g., p.Asn88Lys) may exert dominant-negative effects in heterozygous state, but CMS is typically recessive.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Agrin/LRP4/MuSK signaling in AChR clustering
• Neuromuscular junction development and maintenance
• Dystrophin-associated glycoprotein complex
Protein Summary
Rapsyn is a 412-amino-acid intracellular protein containing tetratricopeptide repeats (TPRs) and a RING-H2 zinc finger domain. It self-associates and binds to the cytoplasmic loop of AChR subunits, promoting receptor aggregation at the postsynaptic membrane. Rapsyn also interacts with MuSK, LRP4, and dystroglycan to stabilize the NMJ. Mutations disrupt these interactions, leading to CMS.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| RAPSN Knockout HEK293 Cell Line | EDJ-KQ14994 | Human | 5913 | Details Get a Quote |
| RAPSN Knockout K-562 Cell Line | EDJ-KZ422 | Human | 5913 | Details Get a Quote |
| RAPSN Knockout HeLa Cell Line | EDJ-KQ54294 | Human | 5913 | Details Get a Quote |
| RAPSN Knockout A-549 Cell Line | EDJ-KQ62790 | Human | 5913 | Details Get a Quote |
| RAPSN Knockout HCT 116 Cell Line | EDJ-KQ71254 | Human | 5913 | Details Get a Quote |
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