How mitochondria import hydrophilic and hydrophobic proteins
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Updated: Sep 29, 2026

Measurement of Protein Import Capacity of Skeletal Muscle Mitochondria
Published on: January 7, 2022
Agnieszka Chacinska1, Nikolaus Pfanner, Chris Meisinger
1Institut für Biochemie und Molekularbiologie, Universität Freiburg, Hermann-Herder-Str. 7, D-79104 Freiburg, Germany.
Abstract:
Most mitochondrial proteins are nuclear encoded and have to be transported into the organelle after synthesis on cytosolic ribosomes. Three multimeric protein complexes have been identified that import precursor proteins destined for the mitochondria: the TOM complex in the outer membrane and two TIM complexes in the inner membrane. Recent work has provided a detailed view of the different mechanisms operating during the import of the two major classes of mitochondrial proteins--hydrophilic proteins with cleavable presequences and hydrophobic proteins with multiple internal signals.
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