The Mechanism of PINK1 Localization on the Outer Membrane of Mitochondria

Objective To study the specific mechanism of PTEM-induced putative kinase 1(PINK1) located to the outer membrane of damaged mitochondria. Methods Cultured HEK293T cells were transfected with plasmids expressing different proteins, following with DMSO or CCCP treatment. Western blot and coimmuoprecipitation were used to detect the expression and interaction of proteins. Results Full length PINK1, but not its mitochondria targeting sequence (MTS) & trans-membrane (TM) deleted forms or other outer mitochondria outer membrane proteins, could interact with Tom40 upon CCCP treatment and the interaction ability was more than 20 times stronger than that of DMSO control. When the added CCCP is washed out, the interaction between full length PINK1 and Tom40 declined rapidly. PINK1 with removed or mutated TM can interact with Tom40 even in the absence of CCCP. Conclusion The accumulated PINK1 on the outer membrane of damaged mitochondria is just stuck on the TOM complex instead of integrated into the lipid bilayer.