By mediating interactions with the extracellular environment and facilitating signalling pathways, cell surface proteins play key roles in embryonic stem (ES) cell biology. These proteins are essential for cell adhesion, communication, and differentiation. Glycosphingolipids (GSLs), including SSEA-1 (stage-specific embryonic antigen-1) and SSEA-4, are glycolipids expressed on the surface of undifferentiated ES cells. They serve as easily detected surface markers of pluripotency and are commonly used for identifying and isolating ES cells. Integrins-a family of cell surface receptors that mediate cell-cell and cell-matrix adhesion- are also expressed in ES cells with α6β1 and αvβ5 integrins involved in adhesion to ECM proteins like laminin and fibronectin. These ECM interactions are essential for maintaining ES cell attachment and pluripotency. CD9 and CD81 are tetraspanin proteins involved in cell adhesion and signal transduction. Both CD9 and CD81 are expressed on the surface of ES cells and are implicated in the regulation of cell proliferation and maintenance of pluripotency. Stage-specific embryonic antigen-3 (SSEA-3) is another glycolipid antigen expressed on the surface of ES cells. Its expression decreases upon differentiation, making it a useful marker for tracking pluripotency status. Epithelial Cell Adhesion Molecule (EpCAM, also known as CD326) is a cell surface glycoprotein that is highly expressed in undifferentiated ES cells. It plays a role in cell adhesion and is used as a marker for the enrichment of pluripotent stem cells. EpCAM is involved in mediating cell-cell adhesion in ES cells, participating in the formation of cell-cell junctions and adhesion complexes that adhere ES cells together in colonies. This adhesion is important for maintaining ES cell colonies and preventing differentiation. Additionally, EpCAM can influence the activation of the Wnt/β-catenin pathway, which plays a role in maintaining stem cell identity and promoting self-renewal. Thy-1 (CD90) is a cell surface protein involved in cell-cell interactions and signalling and implicated in ES cell adhesion and pluripotency maintenance. leukaemia Inhibitory Factor Receptor (LIFR), the receptor for leukaemia inhibitory factor (LIF), is found on the surface of ES cells, and its activation initiates the JAK-STAT signalling pathway, promoting self-renewal. Fibroblast Growth Factor Receptors (FGFRs) are essential for signalling pathways involved in ES differentiation and self-renewal. FGF signalling plays a dual role in ES cell biology, influencing both pluripotency and lineage specification. Cell surface Notch Receptors and their ligands are also involved in cell-cell communication and lineage specification in ES cells. Notch signalling can influence ES cell fate decisions and promote differentiation into specific cell types. CD44 is a cell surface glycoprotein involved in cell adhesion and migration. CD44 can interact with extracellular matrix components like hyaluronic acid (HA) with this interaction important for the localization and anchoring of ES cells within their niche in vivo. CD44-HA interactions are also thought to play a role in the maintenance of pluripotent stem cell properties and the regulation of self-renewal. Finally, Sialyl-Lewis X (SLeX) is a cell surface carbohydrate antigen expressed on the surface of undifferentiated ES cells. It is involved in cell adhesion and may contribute to ES cell homing during development. Explore our full ESCs surface markers product range below and discover more, for less.