TOMM34 Human

Mitochondria are essential organelles responsible for producing the energy required for various cellular processes. Most mitochondrial proteins are encoded by nuclear DNA, synthesized in the cytosol, and subsequently imported into the mitochondria. The translocase of the outer mitochondrial membrane (TOM) complex facilitates this import process. TOMM34 is one of the key proteins in this complex.

TOMM34 is a 34 kDa protein that contains two domains of three tetratricopeptide repeat (TPR) motifs each, separated by a hinge region . These TPR motifs are characterized by a loose 34-amino acid consensus motif. The C-terminal TPR domain is predicted to form a chaperone-binding dicarboxylate clamp, establishing salt bridges with acidic side chains on the peptide ligand from the chaperone .

TOMM34 interacts with heat shock proteins HSP70 and HSP90, which are protein chaperones with ATPase activities that direct the trafficking of substrate proteins to various organelles and cellular locations . This interaction is crucial for the import of nuclear-encoded mitochondrial proteins.

The human TOMM34 gene was cloned by searching an EST database for sequences similar to yeast Tom70 and Tom72, followed by PCR of a fetal cDNA library . The deduced 309-amino acid protein has a calculated molecular mass of 34 kDa. Western blot analysis of fractionated rat liver detected TOMM34 in the outer mitochondrial membrane fraction .

TOMM34 functions in a protein complex required for the import of nuclear-encoded mitochondrial proteins . It binds to mature portions of mitochondrial proteins, facilitating their import into the mitochondria. This process is essential for maintaining mitochondrial function and cellular energy production.