Figure 1
From: ZnT2 is a critical mediator of lysosomal-mediated cell death during early mammary gland involution
ZnT2 accumulates Zn in lysosomes and mitochondria in mouse mammary glands during involution.
(a) Mammary glands (~0.1–0.2 g) from virgin, lactating and 24- and 48 h involuting mice were digested in nitric acid and Zn concentration was measured by atomic absorption spectroscopy. Data represent mean μg Zn/g tissue ± SD; n = 5/group, *P < 0.05, n.s., not significant. (b)–(e) Lysosome- and mitochondria-enriched fractions were isolated from lactating and 24- and 48 h involuting mammary glands by differential centrifugation. (b) Lysosomal Zn concentration from lactating and involuting mammary glands. Fractions were digested in nitric acid and concentration was measured by atomic absorption spectroscopy. Data represent mean μg Zn/mg protein ± SD; n = 4/group, *P < 0.05. (c) Representative immunoblot of ZnT2 and Lamp1 (lysosomal marker) in lysosome-enriched fractions isolated from lactating and involuting mammary glands. β-actin was used as a loading control and ratios of signal intensities are reported under the blot. (d) Isolated mitochondria-enriched fractions from lactating and involuting mammary glands were digested in nitric acid and Zn concentration was measured by atomic absorption spectroscopy. Data represent mean μg Zn/mg protein ± SD; n = 3/group, *P < 0.05. (e) Protein abundance of ZnT2 in mitochondria-enriched fractions isolated from lactating and involuting mammary glands was determined by immunoblot and expressed relative to the mitochondrial marker succinate dehydrogenase (SDH). Ratios of signal intensities are reported under the blot.
