CD9
GeneName
CD9
Summary
CD9, also known as p24, MRP1, or MRP-1, is a 25 kDa tetraspanin protein that is widely expressed in various tissues, including platelets, immune cells, and neurons. It is localised to the plasma membrane and is involved in multiple biological processes such as cell adhesion, platelet activation, and the regulation of macrophage migration. CD9 plays a role in the fusion of sperm to egg plasma membranes during fertilisation and is implicated in glial cell migration and myoblast fusion during skeletal muscle regeneration. Additionally, it is associated with extracellular vesicles and is involved in receptor internalisation and the assembly of paranodal junctions, contributing to cell-cell interactions and signalling pathways.
Importance
CD9 is relevant to: - Fertility and reproductive biology due to its role in sperm-egg recognition and fusion - Immune response modulation as it influences macrophage migration and platelet activation - Neurobiology, particularly in oligodendrocyte development and glial cell migration - Cancer research, where it may affect cell adhesion and metastasis through its integrin binding capabilities - Tissue regeneration processes, including skeletal muscle repair and the regulation of cell population dynamics
Top Products
For researchers investigating CD9, we highly recommend the top-selling recombinant antibody, Anti-CD9 antibody [EPR23105-121] (ab236630). This antibody has been validated in knockout models, ensuring its reliability for your experiments. It is suitable for a variety of applications, including Western blotting (WB), flow cytometry (FC), immunocytochemistry (ICC), immunohistochemistry (IHC), and immunoprecipitation (IP). With 179 citations, this antibody is well-regarded in the research community, making it an excellent choice for those studying CD9.
Abcam Product Citation Summary
The data indicates that CD9 is being studied in various contexts, particularly in human cells and tissues, including gastric carcinoma and exosomes derived from cytotrophoblasts and serum. The use of immunocytochemistry and immunofluorescence in human WJ-MSCs highlights its role in stem cell differentiation. Additionally, there is some research involving CD9 in mouse models, particularly related to serum exosomes.
Abcam Product Citation Table
Function
Integral membrane protein associated with integrins, which regulates different processes, such as sperm-egg fusion, platelet activation and aggregation, and cell adhesion (PubMed:14575715, PubMed:18541721, PubMed:8478605). Present at the cell surface of oocytes and plays a key role in sperm-egg fusion, possibly by organizing multiprotein complexes and the morphology of the membrane required for the fusion (By similarity). In myoblasts, associates with CD81 and PTGFRN and inhibits myotube fusion during muscle regeneration (By similarity). In macrophages, associates with CD81 and beta-1 and beta-2 integrins, and prevents macrophage fusion into multinucleated giant cells specialized in ingesting complement-opsonized large particles (PubMed:12796480). Also prevents the fusion between mononuclear cell progenitors into osteoclasts in charge of bone resorption (By similarity). Acts as a receptor for PSG17 (By similarity). Involved in platelet activation and aggregation (PubMed:18541721). Regulates paranodal junction formation (By similarity). Involved in cell adhesion, cell motility and tumor metastasis (PubMed:7511626, PubMed:8478605).
Post-translational modifications
Palmitoylated at a low, basal level in unstimulated platelets. The level of palmitoylation increases when platelets are activated by thrombin (in vitro). The protein exists in three forms with molecular masses between 22 and 27 kDa, and is known to carry covalently linked fatty acids (PubMed:11959120). Palmitoylation by ZDHHC2 regulates CD9 expression, association with other tetraspanin family proteins and function in cell adhesion (PubMed:18508921).
Sequence Similarities
Belongs to the tetraspanin (TM4SF) family.
Tissue Specificity
Detected in platelets (at protein level) (PubMed:19640571). Expressed by a variety of hematopoietic and epithelial cells (PubMed:19640571).
Cellular localization
- Cell membrane
- Multi-pass membrane protein
- Membrane
- Multi-pass membrane protein
- Secreted
- Extracellular exosome
- Present at the cell surface of oocytes. Accumulates in the adhesion area between the sperm and egg following interaction between IZUMO1 and its receptor IZUMO1R/JUNO.
Alternative names
CD9, MIC3, TSPAN29, GIG2, CD9 antigen, 5H9 antigen, Cell growth-inhibiting gene 2 protein, Leukocyte antigen MIC3, Motility-related protein, Tetraspanin-29, p24, MRP-1, Tspan-29