RT Journal Article SR Electronic T1 Quantification of cristae architecture reveals time-dependent characteristics of individual mitochondria JF Life Science Alliance JO Life Sci. Alliance FD Life Science Alliance LLC SP e201900620 DO 10.26508/lsa.201900620 VO 3 IS 7 A1 Mayuko Segawa A1 Dane M Wolf A1 Nan W Hultgren A1 David S Williams A1 Alexander M van der Bliek A1 David B Shackelford A1 Marc Liesa A1 Orian S Shirihai YR 2020 UL https://www.life-science-alliance.org/content/3/7/e201900620.abstract AB Recent breakthroughs in live-cell imaging have enabled visualization of cristae, making it feasible to investigate the structure–function relationship of cristae in real time. However, quantifying live-cell images of cristae in an unbiased way remains challenging. Here, we present a novel, semi-automated approach to quantify cristae, using the machine-learning Trainable Weka Segmentation tool. Compared with standard techniques, our approach not only avoids the bias associated with manual thresholding but more efficiently segments cristae from Airyscan and structured illumination microscopy images. Using a cardiolipin-deficient cell line, as well as FCCP, we show that our approach is sufficiently sensitive to detect perturbations in cristae density, size, and shape. This approach, moreover, reveals that cristae are not uniformly distributed within the mitochondrion, and sites of mitochondrial fission are localized to areas of decreased cristae density. After a fusion event, individual cristae from the two mitochondria, at the site of fusion, merge into one object with distinct architectural values. Overall, our study shows that machine learning represents a compelling new strategy for quantifying cristae in living cells.