Pitts Lauren R, Frondoni Julia, Nguyen Alexander T, Wehman Ann M
Biological Sciences, University of Denver, Denver, Colorado, United States.
MicroPubl Biol. 2023 Mar 24;2023. doi: 10.17912/micropub.biology.000779. eCollection 2023.
Cells release extracellular vesicles (EVs) from their surface, but the mechanisms that govern EV release by plasma membrane budding are poorly understood. The lipid flippase TAT-5 inhibits EV release from the plasma membrane in , but how the level of flippase activity regulates EV release was unknown. We generated point mutations in the DGET motif of TAT-5 predicted to lead to a partial or complete loss of ATPase activity. We discovered that mutants were sterile, while mutants produced embryos that arrested during development. Using degron-based reporters, we found that EV release was increased in mutant embryos and that phagocytosis was also disrupted. These data suggest that a low level of flippase activity can promote fertility, while a higher level of flippase activity is required to inhibit EV release, allow phagocytosis, and carry out embryonic development.
细胞从其表面释放细胞外囊泡（EVs），但通过质膜出芽来控制EV释放的机制却知之甚少。脂质翻转酶TAT-5在[具体生物]中抑制从质膜释放EVs，但翻转酶活性水平如何调节EV释放尚不清楚。我们在TAT-5的DGET基序中产生了点突变，预计会导致ATP酶活性部分或完全丧失。我们发现[具体突变类型1]突变体是不育的，而[具体突变类型2]突变体产生的胚胎在发育过程中停滞。使用基于降解子的报告基因，我们发现在[具体突变类型1]突变体胚胎中EV释放增加，并且吞噬作用也受到破坏。这些数据表明，低水平的翻转酶活性可以促进生育能力，而抑制EV释放、允许吞噬作用和进行胚胎发育则需要更高水平的翻转酶活性。
