The Role And Mechanism Of Mitochondrial Membrane Protein Atad3a In Mouse T Cells

Objective:To study the important role and mechanism of mitochondrial membrane protein Atad3a in T cell development and anti-tumor immunity response.Methods:We used the Cre-Loxp system to construct the mice with conditional knock-out of Atad3a in the T cell(Lckcre Atad3a^fl/fl,KO mice),and qualitatively analyzed the knockout of the gene Atad3a using agarose gel electrophoresis and Western Blot experiments.Then we took the thymus of KO mice and wild-type mice(Atad3a^fl/fl,WT mice)to made a single cell suspension,and used flow cytometry to detect the proportion and number of T cell subpopulations;using chicken ovalbumin expression B16(B16-OVA)melanoma model to detect the anti-tumor immunity of Atad3a knock-out T cells;Western Blot was used to detect the expression level of downstream proteins related to mitophagy,and the Immunoprecipitation was used to detect the role of AGK and Atad3a relationship.Results:The expression of Atad3a protein completely disappeared in mice with conditional knock-out of Atad3a in the T cell;the thymus development of KO mice was abnormal,the total number of thymus cells was significantly reduced,and the frequency of Double positive(DP)cells,CD8⁺and CD4⁺T cells in the thymus was significantly reduced.Double negative(DN)cells increased significantly,in which DN3 cells increased significantly,and DN4 cells decreased significantly.The results of the B16-F10 tumor model show that Atad3a plays an important role in the anti-tumor immune response of T cells in vivo,and the deletion of Atad3a suppresses the proliferation and the anti-tumor cell response of T cells in vivo.Western Blot and Immunoprecipitation show that AGK can increase the phosphorylation level of Atad3a,thereby inhibiting Pink1-mediated mitochondrial autophagy.Conclusions:Atad3a suppresses Pink1-dependent mitophagy under the regulation of AGK,thus maintaining the normal development and anti-tumor immune function of T cells.