Fig. 3. LETM2 is a mitochondrial protein that is expressed preferentially in testis and sperm. (A) Scheme of LETM1, LETM2, and LETM2S. Red, blue, orange and green boxes represent putative presequences, hydrophobic segments, leucine-zipper motifs and EF-hand motifs, respectively. (B) Poly(A) RNA from adult rat tissues was hybridized using a radioactive probe recognizing LETM2. The blot was also hybridized with a control probe recognizing β-actin. (C) Total-cell lysates from various rat tissues were subjected to immunoblotting using antibodies against LETM2, LETM1 and GAPDH. (D) Total cell lysates from the indicated cell lines were analyzed by immunoblotting using antibodies against LETM2, LETM1 and Hsp60. (E) Total-cell lysates from HeLa cells transfected with vector (lane 1), or with plasmid expressing LETM2 (lane 2) or LETM2S (lane 3), and rat testis homogenates (lane 4) were subjected to immunoblotting using anti-LETM2 antibody. Black and gray arrowheads indicate LETM2 and LETM2S, respectively. (F) HeLa cells transfected with LETM2 (a-c) or LETM2S expression plasmid (d-f) were fixed, permeabilized and immunostained with antibodies against LETM2 and cytochrome c. Images were collected using confocal microscopy. Scale bar, 10 µm.