GTP Binding Protein 5 (GTPBP5)

Small G proteins, such as GTPBP5, act as molecular switches that play crucial roles in the regulation of fundamental cellular processes such as protein synthesis, nuclear transport, membrane trafficking, and signal transduction.By searching human databases for homologs of Escherichia coli Obg proteins, Hirano et al. (2006) identified GTPBP5, which they called OBGH1. The deduced 406-amino acid protein contains an N-terminal mitochondria-localization signal, followed by a glycine-rich region, and a GTPase domain with 5 characteristic subdomains. Epitope-tagged GTPBP5 localized to mitochondria.Hirano et al. (2006) demonstrated that recombinant GTPBP5 showed GTPase activity in vitro. RNA interference of GTPBP5 in HeLa cells resulted in elongated mitochondria and abnormal nuclear morphologies.