Objective: Autophagy is a major intracellular catabolic pathway governed by the sequential actions of proteins encoded by autophagy-related genes (Atg). ATG9, the only transmembrane protein involved in this process, regulates phospholipid translocation to autophagosomes during the early phases of autophagy. In mammals, two Atg9 isoforms have been reported: Atg9a and Atg9b. In this study, we examined whether the molecular and cellular characteristics of these two isoforms differed in mice. Methods: Whole uteri were collected on days 1, 4, and 8 of pregnancy and from ovariectomized mice injected with vehicle, progesterone, or 17β-estradiol. Cells from reproductive tissues, such as granulosa cells, uterine epithelial cells (UECs), uterine stromal cells (USCs), and oocytes were collected. Two human uterine cell lines were also used in this analysis. Reverse transcription-polymerase chain reaction tests, Western blotting, and immunofluorescence staining were performed. Serum starvation conditions were used to induce autophagy in primary cells. Results: Atg9a and Atg9b were expressed in multiple mouse tissues and reproductive cells. Neither Atg9A nor Atg9B significantly changed in response to steroid hormones. Immunofluorescence staining of the UECs and USCs showed that ATG9A was distributed in a punctate-like pattern, whereas ATG9B exhibited a pattern of elongated tubular shapes in the cytoplasm. In human cancer cell lines, ATG9B was undetectable, whereas ATG9A was found in all cell types examined. Conclusion The Atg9 isoforms exhibited distinct subcellular localizations in UECs and may play different roles in autophagy. Notably, human uterine cells exhibited reduced ATG9B expression, suggesting that this suppression may be due to epigenetic regulation.

Objective: Autophagy is a major intracellular catabolic pathway governed by the sequential actions of proteins encoded by autophagy-related genes (Atg). ATG9, the only transmembrane protein involved in this process, regulates phospholipid translocation to autophagosomes during the early phases of autophagy. In mammals, two Atg9 isoforms have been reported: Atg9a and Atg9b. In this study, we examined whether the molecular and cellular characteristics of these two isoforms differed in mice. Methods: Whole uteri were collected on days 1, 4, and 8 of pregnancy and from ovariectomized mice injected with vehicle, progesterone, or 17β-estradiol. Cells from reproductive tissues, such as granulosa cells, uterine epithelial cells (UECs), uterine stromal cells (USCs), and oocytes were collected. Two human uterine cell lines were also used in this analysis. Reverse transcription-polymerase chain reaction tests, Western blotting, and immunofluorescence staining were performed. Serum starvation conditions were used to induce autophagy in primary cells. Results: Atg9a and Atg9b were expressed in multiple mouse tissues and reproductive cells. Neither Atg9A nor Atg9B significantly changed in response to steroid hormones. Immunofluorescence staining of the UECs and USCs showed that ATG9A was distributed in a punctate-like pattern, whereas ATG9B exhibited a pattern of elongated tubular shapes in the cytoplasm. In human cancer cell lines, ATG9B was undetectable, whereas ATG9A was found in all cell types examined. Conclusion The Atg9 isoforms exhibited distinct subcellular localizations in UECs and may play different roles in autophagy. Notably, human uterine cells exhibited reduced ATG9B expression, suggesting that this suppression may be due to epigenetic regulation.

Objective: Autophagy is a major intracellular catabolic pathway governed by the sequential actions of proteins encoded by autophagy-related genes (Atg). ATG9, the only transmembrane protein involved in this process, regulates phospholipid translocation to autophagosomes during the early phases of autophagy. In mammals, two Atg9 isoforms have been reported: Atg9a and Atg9b. In this study, we examined whether the molecular and cellular characteristics of these two isoforms differed in mice. Methods: Whole uteri were collected on days 1, 4, and 8 of pregnancy and from ovariectomized mice injected with vehicle, progesterone, or 17β-estradiol. Cells from reproductive tissues, such as granulosa cells, uterine epithelial cells (UECs), uterine stromal cells (USCs), and oocytes were collected. Two human uterine cell lines were also used in this analysis. Reverse transcription-polymerase chain reaction tests, Western blotting, and immunofluorescence staining were performed. Serum starvation conditions were used to induce autophagy in primary cells. Results: Atg9a and Atg9b were expressed in multiple mouse tissues and reproductive cells. Neither Atg9A nor Atg9B significantly changed in response to steroid hormones. Immunofluorescence staining of the UECs and USCs showed that ATG9A was distributed in a punctate-like pattern, whereas ATG9B exhibited a pattern of elongated tubular shapes in the cytoplasm. In human cancer cell lines, ATG9B was undetectable, whereas ATG9A was found in all cell types examined. Conclusion The Atg9 isoforms exhibited distinct subcellular localizations in UECs and may play different roles in autophagy. Notably, human uterine cells exhibited reduced ATG9B expression, suggesting that this suppression may be due to epigenetic regulation.

The maturation process of mammalian oocytes accompanies an extensive rearrangement of the cytoskeleton and associated proteins. As this process requires a delicate interplay between the cytoskeleton and its regulators, it is often targeted by various external and internal adversaries that affect the congression and/or segregation of chromosomes. Asymmetric cell division in oocytes also requires specific regulators of the cytoskeleton, including formin-2 and small GTPases. Recent literature providing clues regarding how actin filaments and microtubules interact during spindle migration in mouse oocytes are highlighted in this review.
Actin Cytoskeleton ; Animals ; Asymmetric Cell Division ; Cytoskeleton ; GTP Phosphohydrolases ; Humans ; Mice ; Microtubules ; Monomeric GTP-Binding Proteins ; Nerve Tissue Proteins ; Oocytes ; Proteins