Thymocyte selection associated protein

Thymocyte-expressed molecule involved in selection (THEMIS) is a protein coding gene that plays a regulatory role in positive and negative T-cell selection during late thymocyte development (1). THEMIS is located on human chromosome 6q22.33. It is a member of a new metazoan gene family and is required for completion of thymocyte positive selection (2). THEMIS contains a tandem repeat of a unique globular domain which includes cysteine motif that defines a family consisting of five uncharacterized vertebrae proteins that have orthologs in most animal species (2).  THEMIS appears to be related to TCR signaling and, because it is quickly phosphorylated after TCR stimulation, it is necessary for optimal TCR-driven calcium mobilization as well as being necessary for activation of the ErK-Kinase (3). 

Recently it was reported that THEMIS is essential for the transition of CD4⁺ CD8⁺ double-positive (DP) cells to MHC class I-restricted CD4^- CD8⁺ and MHC class II-restricted CD4⁺ CD8^- single positive (SP) cells (4) In agreement with these findings THEMIS deficient thymocytes showed defective positive selection which caused fewer thymocytes to reach maturation (5). In these mice, CD4SP thymocyte maturation was more severely affected than CD8SP due to the fact that sustained signaling is essential for CD4SP thymocyte development (6). A large percentage of THEMIS-deficient cells had a CD4(+)CD25(+)Foxp3(t) regulatory and CD62L(10)CD44(hi) memory phenotypes than compared to wild type of T cells (3). THEMIS is expressed in thymocytes between the Pre-T cell antigen receptor (pre-TCR) and positive selection checkpoints.   THEMIS is approximately a 77kDa protein (641 amino acids).

The THEMIS antibodies were generated against purified THEMIS protein. THEMIS are affinity purified over immobilized antigen based chromatography, and the purified immunoglobulins are stabilized in antibody stabilization buffer. FabGennix Int. Inc. will also provide limited quantities of antigenic blocking protein for THEMIS antibody. Antibodies to THEMIS (THMS-101AP) will label ~77kDa protein in Western blot positive control samples for THEMIS and several other tissues. FabGennix Inc. will also conjugate antibodies with secondary enzymes (alk-Pase or HRP) or fluorescent probes upon request at nominal cost.

For research use only, not for diagnostic or therapeutic use.