During thymocyte development, may support the positive selection of CD4 and CD8 T cells (PubMed:16509771). May play a role in mitochondrial DNA segregation in hematopoietic tissues (PubMed:25808953). Binds GTP (PubMed:11238997). Interacts with BAD, BAK1, BAX, BCL2, BCL2L1/Bcl-xL and BCL2L11/BimEL (PubMed:16509771). The interaction with BAX is increased, when cells initiate apoptosis upon IL2 withdrawal (PubMed:16509771). The mitochondrial localization originally reported was observed with C-terminally tagged protein and was not confirmed in later publications. Expressed in thymus (in thymocytes), spleen (in splenocytes), lymph node and, at lower levels, in lung (PubMed:16509771, PubMed:25808953). Highly expressed in T lymphocytes (PubMed:16509771). Up-regulated upon the maturation of CD4/CD8 double-positive to CD4 single-positive thymocytes. By BCR-ABL oncogene. Belongs to the TRAFAC class TrmE-Era-EngA-EngB-Septin-like GTPase superfamily. AIG1/Toc34/Toc159-like paraseptin GTPase family. IAN subfamily.