2B4/CD244 Extracellular Domain (human, recombinant)

2B4, also known as CD244, is a cell surface receptor and a member of the signaling lymphocytic activation molecule (SLAM) receptor family (SLAMF).¹ It is comprised of an extracellular domain containing immunoglobulin (Ig) variable-like (IgV) and Ig constant 2-like (IgC2) motifs and several glycosylation sites, a membrane-spanning region, and a cytoplasmic domain containing serine, tyrosine, and threonine phosphorylation sites.² It is expressed on natural killer (NK) cells, certain T cells, monocytes, basophils, and eosinophils. 2B4 has an activating role when the adapter protein SLAM-associated protein (SAP) is present and bound to intracellular tyrosine-based switch motifs (ITSM) on the cytoplasmic domain.¹ When SAP is absent, SHP-1, SHP-2, SHIP-1, or CsK are able to bind, which leads to inhibitory signaling. 2B4 has cis- and trans-interactions with the cell surface receptor CD48 during the initiation and continuation of allergic reactions. It has a complex role in cancer, with male, but not female, CD244^-/- mice rejecting tumor cells in a xenograft model, however, its role is primarily inhibitory in tumor-associated immune cells.² The expression of CD244 is decreased in NK cells from patients with multiple myeloma or systemic lupus erythematosus (SLE).¹ 2B4 is associated with X-linked lymphoproliferative disease (XLPD), which is characterized by a mutation in SAP that prevents it from binding to 2B4.³ Cayman’s 2B4/CD244 Extracellular Domain (human, recombinant) protein can be used for ELISA. This protein consists of 211 amino acids, has a calculated molecular weight of 23.8 kDa, and a predicted N-terminus of Cys22 after signal peptide cleavage. By SDS-PAGE, under reducing conditions, the apparent molecular mass of the protein is approximately 45-50 kDa due to glycosylation.

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1. Pahima, H., Puzzovio, P.G., and Levi-Schaffer, F. 2B4 and CD48: A powerful couple of the immune system. Clin. Immunol. 204, 64-68 (2019).

2. Buller, C.W., Mathew, P.A., and Mathew, S.O. Roles of NK cell receptors 2B4 (CD244), CS1 (CD319), and LLT1 (CLEC2D) in cancer. Cancers (Basel) 12(7), 1755 (2020).

3. Mathew, P.A. Regulation of NK cell function by 2B4 (CD244) receptor. Trends Immunol. 9, 25-32 (2008).