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. 2022 Oct;36(10):e22533.
doi: 10.1096/fj.202200528R.

Pore-forming protein βγ-CAT promptly responses to fasting with capacity to deliver macromolecular nutrients

Zhi-Hong Shi  1   2 , Zhong Zhao  1   3 , Ling-Zhen Liu  1   2 , Xian-Ling Bian  1   4 , Yun Zhang  1   5
Affiliations

Pore-forming protein βγ-CAT promptly responses to fasting with capacity to deliver macromolecular nutrients

Zhi-Hong Shi et al. FASEB J. 2022 Oct.

Abstract

During animal fasting, the nutrient supply and metabolism switch from carbohydrates to a new reliance on the catabolism of energy-dense lipid stores. Assembled under tight regulation, βγ-CAT (a complex of non-lens βγ-crystallin and trefoil factor) is a pore-forming protein and trefoil factor complex identified in toad Bombina maxima. Here, we determined that this protein complex is a constitutive component in toad blood, that actively responds to the animal fasting. The protein complex was able to promote cellular albumin and albumin-bound fatty acid (FA) uptake in a variety of epithelial and endothelial cells, and the effects were attenuated by a macropinocytosis inhibitor. Endothelial cell-derived exosomes containing largely enriched albumin and FAs, called nutrisomes, were released in the presence of βγ-CAT. These specific nutrient vesicles were readily taken up by starved myoblast cells to support their survival. The results uncovered that pore-forming protein βγ-CAT is a fasting responsive element able to drive cell vesicular import and export of macromolecular nutrients.

Keywords: albumin; fasting; fatty acid; nutrient; pore-forming protein.

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References

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