ATAD3B is a primate-specific mitochondrial membrane protein that functions as a mitophagy receptor and negative regulator of ATAD3A activity. Under normal conditions, ATAD3B hetero-oligomerizes with ATAD3A, promoting ATAD3B targeting to the mitochondrial intermembrane space 1. When cells experience oxidative stress or mtDNA damage, ATAD3B-ATAD3A hetero-oligomerization is reduced, exposing ATAD3B's C-terminus at the mitochondrial outer membrane where it binds LC3 through its LIR motif to initiate PINK1-independent mitophagy 1. This mechanism enables selective clearance of damaged mitochondrial DNA, particularly relevant in mitochondrial diseases like MELAS 1. ATAD3B serves as a biomarker of pluripotent embryonic stem cells and supports mitochondrial stemness properties by negatively regulating ATAD3A function 2. The protein's expression is associated with reduced mitochondrial metabolism, low mtDNA copies, and fragmentated mitochondrial networks characteristic of stem cells 2. Clinically, ATAD3B dysfunction contributes to neurological syndromes through altered mitochondrial dynamics and cholesterol metabolism 3, while its expression patterns serve as prognostic markers in lymphomas 45.