GTP-binding proteins (GTPases) have been detected in the mitochondria of @entity1 placenta. It has been proposed that @entity20600 interacts with GTPases in the mitochondrion to modulate contact site function, however, their identity and location is not known. In this study, we investigated the location of GTPases in mitochondria from term placentae as well as the expression of mitochondrial GTPases in mid-term placentae. Mitochondria obtained from @entity1 term and mid-term placentae were purified by sedimentation. Sub-mitochondrial vesicles prepared from ruptured and sonicated mitochondria were separated by ultracentrifugation in @entity969 density gradients. The location of membrane vesicles was determined using marker enzymes. Mitochondrial proteins were separated by SDS-PAGE. Western blots were incubated in [alpha-(32)P]-GTP and detected using autoradiography or antibodies against known GTPases and @entity20600 followed by enhanced chemiluminescence. [alpha-(32)P]-GTP bound 24 and 28 kDa proteins located in the outer membrane. The G(salpha)antibody detected 42.5, 53 and 67 kDa proteins. The G(ialpha)antibody identified a 40.5 kDa band in contact sites and the outer membrane, as well as 55 and 105 kDa proteins in contact site vesicles. The @entity5856 antibody detected a 28 kDa protein, mainly in the outer membrane. @entity20600 migrated at 30 kDa. G(ialpha)and @entity5856 were detected in mitochondria from both term and mid-term placentae. The location of @entity20600 and GTPases leave open the possibility that these proteins interact in contact sites and may also be responding to extra-mitochondrial signals. @entity5856 and G(ialpha)are expressed by mid-term in @entity1 placentae and may be necessary for placental functions at this stage of development. It will be important in future experiments to characterise the physiological functions of these @entity3007 -binding proteins in the mitochondria of @entity1 placenta.

GTP-binding proteins G(salpha), G(ialpha), and XXXX identified in mitochondria of @entity1 placenta.

@entity1 :: ('9606', 'Species') :: ['human'] @entity3007 :: ('MESH:D006160', 'Chemical') :: ['GTP'] @entity20600 :: ('7416', 'Gene') :: ['Porin', 'porin'] @entity5856 :: ('5901', 'Gene') :: ['Ran'] @entity969 :: ('MESH:D013395', 'Chemical') :: ['sucrose']
@entity5856 :: (5901,Gene) :: ['Ran']
