|Datasheet||Specific References||Reviews||Related Products||Protocols|
|Vector Type||Mammalian Expression Vector|
|Expression Method||Constiutive ,Stable / Transient|
|Selection In Mammalian Cells||Hygromycin|
FLAG-tag, or FLAG octapeptide, is a polypeptide protein tag that can be added to a protein using recombinant DNA technology. It can be used for affinity chromatography, then used to separate recombinant, overexpressed protein from wild-type protein expressed by the host organism. It can also be used in the isolation of protein complexes with multiple subunits.
A FLAG-tag can be used in many different assays that require recognition by an antibody. If there is no antibody against the studied protein, adding a FLAG-tag to this protein allows one to follow the protein with an antibody against the FLAG sequence. Examples are cellular localization studies by immunofluorescence or detection by SDS PAGE protein electrophoresis.
The peptide sequence of the FLAG-tag from the N-terminus to the C-terminus is: DYKDDDDK (1012 Da). It can be used in conjunction with other affinity tags, for example a polyhistidine tag (His-tag), HA-tag or myc-tag. It can be fused to the C-terminus or the N-terminus of a protein. Some commercially available antibodies (e.g., M1/4E11) recognize the epitope only when it is present at the N-terminus. However, other available antibodies (e.g., M2) are position-insensitive.
CD40, also known as TNFRSF5, is a member of the TNF receptor superfamily which are single transmembrane-spanning glycoproteins. CD40 protein plays an essential role in mediating a broad variety of immune and inflammatory responses including T cell-dependent immunoglobulin class switching, memory B cell development, and germinal center formation. CD40 protein is expressed in B cells, dendritic cells, macrophages, endothelial cells, and several tumor cell lines. Defects in CD40 result in hyper-IgM immunodeficiency type 3 (HIGM3). In addition, CD40/CD40L interaction is found to be necessary for amyloid-beta-induced microglial activation, and thus is thought to be an early event in Alzheimer disease pathogenesis.