| Modification Notes |
A distinct family of interferon-γ (IFN-γ) inducible GTPases, belonging to the GTPase superfamily, are selectively induced by IFN- γ or bacterial lipopolysaccharide (LPS) stimulation. These putative GTPases include TGTP, IRG-47, LRG-47, and IGTP, and they are involved in mediating the celluar innate immune responses. Similar to other GTPases, they contain a characteristic nucleotide-binding domain for GTP and are functionally regulated by the binding and hydrolysis of GTP. In addition, these related proteins also contain significant sequence similarity between themselves, are largely similar in size and yet they are differentially expressed. TGTP, or T-cell specific GTPase, is preferentially expressed in T-cells and is up-regulated in response to TCR cross-linking. IGTP (inducibly expressed GTPase) is expressed predominantly in macrophages, whereas IRG-47 is primarily expressed in all cells derived from B-cell lineages, and LRG-47 is highly expressed in macrophages following IFN-γ stimulation. Two additional proteins IIGP and GTP1 are expressed in mouse embryonic fibroblasts and macrophages and are likewise up-regulated by IFN-γ stimulation. |
