Healthy human oocyte proteostasis
Protein homeostasis (proteostasis) has been observed in mouse oocytes but the mechanisms of proteostasis in human oocytes remain unknown.
The researchers carried out proteostatic activity in human oocytes using over 100 freshly donated oocytes from 21 healthy women aged 19–34 years.
They demonstrate that immature human oocytes show higher proteolytic activity than mature oocytes, which show reduced number of lysosomes and reduced mitochondrial membrane potential.
The authors also show that oocyte maturation is accompanied by rearrangement of mitochondria and proteasomes from the perinuclear area to the cytoplasm.
They also observe that human oocytes contain aggregated proteins within a few enlarged lysosomes distributed throughout the cytoplasm.
The authors propose that reduced organelle activity preserves key cellular components critical for early embryonic development during the prolonged maturation of human oocytes.
https://www.embopress.org/doi/full/10.1038/s44318-025-00493-2
