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Updated: Oct 23, 2025

Measurement of Protein Import Capacity of Skeletal Muscle Mitochondria
Published on: January 7, 2022
Mitochondrial Lon protease is a gatekeeper for proteins newly imported into the matrix
Yuichi Matsushima1, Kazuya Takahashi2, Song Yue2
1Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. matsush5@cclm.med.kyushu-u.ac.jp.
Abstract:
Human ATP-dependent Lon protease (LONP1) forms homohexameric, ring-shaped complexes. Depletion of LONP1 causes aggregation of a broad range of proteins in the mitochondrial matrix and decreases the levels of their soluble forms. The ATP hydrolysis activity, but not protease activity, of LONP1 is critical for its chaperone-like anti-aggregation activity. LONP1 forms a complex with the import machinery and an incoming protein, and protein aggregation is linked with matrix protein import. LONP1 also contributes to the degradation of imported, aberrant, unprocessed proteins using its protease activity. Taken together, our results show that LONP1 functions as a gatekeeper for specific proteins imported into the mitochondrial matrix.
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