A cryptic mitochondrial targeting motif in Atg4D links caspase cleavage with mitochondrial import and oxidative stress.

ABSTRACT: The Atg4 cysteine proteases play crucial roles in the processing of Atg8 proteins during autophagy, but their regulation during cellular stress and differentiation remains poorly understood. We have found that two Atg4 family members--Atg4C and Atg4D--contain cryptic mitochondrial targeting sequences immediately downstream of their canonical (DEVD) caspase cleavage sites. Consequently, caspase-cleaved Atg4D (ΔN63 Atg4D) localizes to the mitochondrial matrix when expressed in mammalian cells, where it undergoes further processing to a ~42 kDa mitochondrial form. Interestingly, caspase cleavage is not needed for Atg4D mitochondrial import, because ~42 kDa mitochondrial Atg4D is observed in cells treated with caspase inhibitors and in cells expressing caspase-resistant Atg4D (DEVA(63)). Using

SUBMITTER: Betin VM 

PROVIDER: S-EPMC3405841 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature