Saltar al contenido
Merck

GTP hydrolysis is essential for protein import into the mitochondrial matrix.

The Journal of biological chemistry (1998-01-27)
N B Sepuri, N Schülke, D Pain
RESUMEN

Protein import into the innermost compartment of mitochondria (the matrix) requires a membrane potential (delta psi) across the inner membrane, as well as ATP-dependent interactions with chaperones in the matrix and cytosol. The role of nucleoside triphosphates other than ATP during import into the matrix, however, remains to be determined. Import of urea-denatured precursors does not require cytosolic chaperones. We have therefore used a purified and urea-denatured preprotein in our import assays to bypass the requirement of external ATP. Using this modified system, we demonstrate that GTP stimulates protein import into the matrix; the stimulatory effect is directly mediated by GTP hydrolysis and does not result from conversion of GTP to ATP. Both external GTP and matrix ATP are necessary; neither one can substitute for the other if efficient import is to be achieved. These results suggest a "push-pull" mechanism of import, which may be common to other post-translational translocation pathways.

MATERIALES
Referencia del producto
Marca
Descripción del producto

Sigma-Aldrich
Guanosine 5′-triphosphate tris salt, ≥93% (HPLC), powder