Components and Mechanisms in Mitochondrial Protein Import
The biogenesis of mitochondrial proteins requires two genetic systems. Less than 5% of mitochondrial proteins are encoded by mitochondrial genes and are synthesized within the organelle. The vast majority of mitochondrial proteins are encoded by nuclear genes and are synthesized as precursor proteins on cytosolic polysomes (Douglas et al., 1986; Rosenberg et al, 1987; Attardi and Schatz, 1988; Pfanner et al., 1988a; Hartl et al., 1989; Pfanner and Neupert, 1989; Lonsdale and Grienenberger, 1992) (Fig. 1). Therefore, several hundred different proteins have to be imported into mitochondria. The transport of precursor proteins into mitochondria comprises a complex series of steps, including targeting, membrane translocation, and assembly of the proteins.
KeywordsPrecursor Protein Mitochondrial Matrix Neurospora Crassa Contact Site Intermembrane Space
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