LY9 (Lymphocyte Antigen 9)
A member of the signaling lymphocytic activation molecule (SLAM) family involved in immune cell regulation
Gene Information Card
| Symbol | LY9 |
|---|---|
| Full Name | Lymphocyte Antigen 9 |
| Gene Type | Protein coding |
| Chromosomal Location | 1q23.3 |
| NCBI Gene ID | 4063 ncbi.nlm.nih.gov/gene/4063 |
| Ensembl ID | ENSG00000122254 |
| UniProt ID | Q9HBG7 |
| OMIM ID | 600684 |
| HGNC ID | 6731 |
| Aliases | SLAMF3, CD229, hly9, mLY9 |
Description
LY9 encodes a cell surface glycoprotein belonging to the signaling lymphocytic activation molecule (SLAM) family. It is expressed on T cells, B cells, natural killer (NK) cells, and other hematopoietic cells. LY9 acts as a self-ligand receptor involved in immune cell adhesion, activation, and differentiation. The protein contains extracellular immunoglobulin-like domains and intracellular immunoreceptor tyrosine-based switch motifs (ITSMs) that recruit adaptor molecules such as SAP and EAT-2 to modulate signaling.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Systemic lupus erythematosus (SLE) | LY9 polymorphisms may alter immune cell signaling and contribute to autoimmunity | GWAS association (PMID: 19838193) |
| Rheumatoid arthritis | Variants in LY9 region linked to increased susceptibility | GWAS (PMID: 24390342) |
| Multiple sclerosis | LY9 SNPs associated with risk in certain populations | Case-control study (PMID: 22539336) |
| Infectious diseases (e.g., HIV) | LY9 expression on T cells may influence viral entry or immune evasion | Expression studies (PMID: 16113227) |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Spleen | 12.5 | Medium |
| Lymph node | 10.8 | Medium |
| Bone marrow | 8.2 | Medium |
| Blood | 7.1 | Low |
| Lung | 3.4 | Low |
| Small intestine | 2.9 | Low |
| Colon | 2.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Jurkat (T-cell leukemia) | 15.3 | High expression |
| Raji (Burkitt lymphoma) | 12.7 | High expression |
| K-562 (chronic myeloid leukemia) | 6.8 | Moderate expression |
| HEK 293 (embryonic kidney) | 0.5 | Very low expression |
| HeLa (cervical carcinoma) | 0.3 | Very low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1015C>T (p.Arg339Cys) | Missense | <0.01% | Unknown; rare variant in population databases |
| c.1246G>A (p.Gly416Ser) | Missense | <0.01% | Unknown; predicted benign |
| c.1573_1575del (p.Phe525del) | In-frame deletion | <0.01% | Unknown; may affect protein structure |
Mutation functional classification
Loss of Function (LOF)
No confirmed loss-of-function mutations reported in ClinVar or COSMIC for LY9.
Gain of Function (GOF)
No confirmed gain-of-function mutations reported.
Dominant Negative (DN)
No confirmed dominant-negative mutations reported.
View complete mutation data：
Gene Ontology (GO)
| • transmembrane signaling receptor activity (GO:0004888) | • protein binding (GO:0005515) |
| • cell adhesion (GO:0007155) | • signal transduction (GO:0007165) |
| • plasma membrane (GO:0005886) | • integral component of membrane (GO:0016021) |
| • T cell costimulation (GO:0031295) | • positive regulation of T cell proliferation (GO:0042102) |
Pathways
• SLAM family signaling pathway (Reactome: R-HSA-2132295)
• Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell (Reactome: R-HSA-198933)
Protein Summary
LY9 (CD229) is a 120 kDa transmembrane glycoprotein with four extracellular immunoglobulin-like domains (two V-set and two C2-set) and a cytoplasmic tail containing three ITSMs. It is predominantly expressed on hematopoietic cells and functions as a homophilic adhesion molecule. Upon ligand binding, LY9 recruits SH2 domain-containing adaptors (SAP, EAT-2) to ITSMs, modulating downstream signaling pathways including PI3K/AKT and MAPK. LY9 plays roles in T-cell and B-cell activation, NK cell cytotoxicity, and immune synapse formation. Alternative splicing generates multiple isoforms.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| LY96 Knockout HEK293 Cell Line | EDJ-KQ3149 | Human | 23643 | Details Get a Quote |
| LY9 Knockout HEK293 Cell Line | EDJ-KQ4378 | Human | 4063 | Details Get a Quote |
| LY9 Knockout HeLa Cell Line | EDJ-KQ53815 | Human | 4063 | Details Get a Quote |
| LY96 Knockout HeLa Cell Line | EDJ-KQ55789 | Human | 23643 | Details Get a Quote |
| LY9 Knockout A-549 Cell Line | EDJ-KQ62295 | Human | 4063 | Details Get a Quote |
| LY96 Knockout A-549 Cell Line | EDJ-KQ64285 | Human | 23643 | Details Get a Quote |
| LY9 Knockout HCT 116 Cell Line | EDJ-KQ70777 | Human | 4063 | Details Get a Quote |
| LY96 Knockout HCT 116 Cell Line | EDJ-KQ72732 | Human | 23643 | Details Get a Quote |
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