Cytosolic subunits of ATP synthase are localized to the cortical endoplasmic reticulum-rich domain of the ascidian egg myoplasm.

Previously, we revealed that p58, one of the ascidian maternal factors, is identical to the alpha-subunit of F1-ATP synthase (ATPα), a protein complex of the inner mitochondrial membrane. In the current study, we used immunological probes for ascidian mitochondria components to show that the ascidian ATPα is ectopically localized to the cytosol. Virtually all mitochondrial components were localized to the mitochondria-rich myoplasm. However, in detail, ATP synthase subunits and the matrix proteins showed different localization patterns. At least at the crescent stage, transmission electron microscopy (TEM) distinguished the mitochondria-less, endoplasmic reticulum (ER)-rich cortical region and the mitochondria-rich internal region. ATPα was enriched in the cortical region and MnSOD was limited to the internal region. Using subcellular fractionation, although all of the mitochondria components were highly enriched in the mitochondria-enriched fraction, a considerable amount of ATPα and F1-ATP synthase beta-subunit (ATPß) were recovered in the insoluble cytoplasmic fraction. Even under these conditions, F1-ATP synthase gamma-subunit (ATPγ) and F0-ATP synthase subunit b (ATPb) were not recovered in the insoluble cytoplasmic fraction. This result strongly supports the exomitochondrial localization of both ATPα and ATPß. In addition, the detergent extraction of eggs supports the idea that these cytosolic ATP synthase subunits are associated with the egg cytoskeleton. These results suggest that the subunits of ATP synthase might play dual roles at different subcellular compartments during early development.

Morphological and phylogenetic diversity of Waminoa and similar flatworms (Acoelomorpha) in the western Pacific Ocean.

The genus Waminoa currently contains two described species, which each contains two types of endosymbiotic algae. Waminoa individuals are basically brown in body color, derived from these algal symbionts, and their body shape has been described as "discoid to obcordate". They have been found as associates of various anthozoans (Cnidaria) in the Indo-Pacific Ocean and the Red Sea. In order to reveal the diversity of the genus Waminoa and their hosts, we conducted phylogenetic and morphological analyses on acoelomate flatworms specimens collected from Japan, Palau and Indonesia. At least 18 Waminoa morphotypes were found on at least 20 anthozoan host species, and two specimens were found on species of two sea stars. Overall, there were two main body shapes of specimens; obcordate, as seen in W. litus and W. brickneri, and the other molar-like with an elongated body. These two body shapes each represented a separate clade in 18S rDNA and mitochondrial cytochrome c oxidase subunit 1 (COI) phylogenetic trees, with W. brickneri included in the obcordate subclade. Automatic Barcode Gap Discovery (ABGD) analyses on COI sequences of our specimens revealed the presence of at least five operational taxonomic units (OTUs). These five OTUs consisted of one large group of all obcordate animals, three OTUs consisting of one specimen each within the molar-like clade, and one large group of the remaining molar-like specimens. Both clades contain numerous morphotypes and were associated with a variety of hosts. Finally, based on genetic distances, the molar-like specimens are considered as an unnamed genus group separate from Waminoa, which needs to be clarified in future studies.

Simultaneous expression of cancer stem cell-like properties and cancer-associated fibroblast-like properties in a primary culture of breast cancer cells.

The importance of cancer-associated fibroblasts (CAFs) in cancer biology has been recently highlighted owing to their critical roles in cancer growth, progression, metastasis, and therapeutic resistance. We have previously established a primary culture of breast cancer cells, which showed epithelial-mesenchymal transition and cancer stem cell-like properties. In this study, we found that the primary culture also showed CAF-like properties. For example, hypoxia inducible factor 1α (HIF1A) and its downstream genes, nuclear factor-kappa B2 (NF-κB2) and BCL2/adenovirus E1B 19 kd-interacting protein 3 (BNIP3), and many enzymes involved in glycolysis, such as GAPDH, LDH, PGAM1, and PKM2, were highly overexpressed in the primary culture. Moreover, media conditioned with the primary culture cells enhanced the growth of breast cancer cells. Similar to previous CAF studies, this enhancement suggested to be occurred through fibroblast growth factor signaling. This MCKH primary culture cell, which showed simultaneous expression of tumorigenic and CAF properties, offers a unique experimental system for studying the biology of CAFs.