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bioRxiv · 10.1101/2022.02.16.480676

A small molecule probe elucidates the role of mitochondrial translocase TIMM44 in PINK1/Parkin regulated mitophagy

Conti, M. A.·Torres, E. R.·van der Bliek, A. M.·Koehler, C.
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Abstract

Neurodegenerative diseases have been linked to a dysfunctional mitochondrial quality control system that is partially maintained by proteins PINK1 and Parkin. Whereas mitophagy pathways are becoming well-characterized, less is known about the molecular mechanisms of PINK1 trafficking in mitochondria. Accordingly, we have used a small molecule probe (MitoBloCK-10/MB-10) that modulates the activity of TIMM44, an essential component of the protein associated motor (PAM) complex for the mitochondrial inner membrane (TIM23) translocase, to characterize PINK1 import. MB-10 did not inhibit the import or degradation of PINK1 in energized mitochondria. However, when mitophagy was induced by the addition of an uncoupler or respiratory inhibitor, MB-10 treatment altered PINK1 trafficking by inhibiting association with the TOM complex and impairing Parkin recruitment and subsequent mitophagy. MB-10 analogs that did not inhibit TIMM44 activity failed to impair mitophagy, thereby assigning specificity to MB-10. Because PINK1 undergoes lateral release from the TIM23 translocon to interact with inner membrane (IM) modulators, our studies support that TIMM44 may be a key regulator and that the PAM complex has a central role in regulating PINK1-dependent mitophagy. Our studies also provide a probe for dissecting PINK1/Parkin events for mitochondria as well as studying PINK1-dependent mitophagy in cell and animal models.

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Conti, M. A., Torres, E. R., van der Bliek, A. M., Koehler, C.. 2022-02-16. A small molecule probe elucidates the role of mitochondrial translocase TIMM44 in PINK1/Parkin regulated mitophagy. https://doi.org/10.1101/2022.02.16.480676

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