The ULK complex-LRRK1 axis regulates Parkin-mediated mitophagy via Rab7 Ser-72 phosphorylation.

Area of Science:

• Cellular Biology
• Molecular Biology
• Autophagy Research

Background:

• Mitophagy selectively removes damaged mitochondria via selective autophagy.
• The ULK complex regulates Parkin-mediated mitophagy, but its role in initiating mitophagosome formation is unclear.
• Rab7 GTPase phosphorylation at Ser-72 is critical for mitophagosome formation, with LRRK1 identified as the responsible kinase.

Purpose of the Study:

• To investigate the role of LRRK1 in Parkin-mediated mitophagy.
• To elucidate the mechanism by which the ULK complex initiates mitophagosome formation.
• To understand the ULK complex-LRRK1 axis in mitophagy regulation.

Main Methods:

• Investigated LRRK1 function downstream of ULK1 and ULK2 in mitophagy.
• Utilized ectopic targeting of active LRRK1 to mitochondria.
• Examined Rab7 Ser-72 phosphorylation in the absence of ATG13.

Main Results:

• LRRK1 functions downstream of ULK1 and ULK2 in Parkin-mediated mitophagy.
• Ectopic expression of active LRRK1 in mitochondria induced Rab7 Ser-72 phosphorylation independently of ATG13.
• Demonstrated that the ULK complex recruits LRRK1 to mitochondria via ATG13 to initiate mitophagosome formation.

Conclusions:

• The ULK complex recruits LRRK1 to mitochondria through ATG13 to initiate mitophagosome formation.
• The ULK complex-LRRK1 axis is a key regulator of Parkin-mediated mitophagy.
• This study clarifies a critical step in the mitophagy pathway, linking ULK complex activity to Rab7 phosphorylation and mitophagosome biogenesis.