Macroautophagy/autophagy, a fundamental process for degradation of macromolecules and organelles, occurs constitutively at a basal level and is upregulated in response to stress. Whether autophagy regulates protein acetylation and microtubule stability in vascular smooth muscle cells (VSMCs) migration, however, remains unknown. Here, we demonstrate that the histone acetyltransferase KAT2A/GCN5 (lysine acetyltransferase 2) binds directly to the autophagosome protein MAP1LC3/LC3 (microtubule associated protein 1 light chain 3) via a conserved LC3-interacting region (LIR) domain. This interaction is required for KAT2A sequestration in autophagosomes and degradation by lysosomal acid hydrolases. Suppression of autophagy results in KAT2A accumulation. KAT2A functions as an acetyltransferase to increase TUBA/α-tubulin acetylation, promote microtubule polymerization and stability, ultimately inhibiting directional cell migration. Our findings indicate that deacetylation of TUBA and perturbation of microtubule stability via selective autophagic degradation of KAT2A are essential for autophagy-promoting VSMC migration.

Abbreviations: ACTB: actin beta; ATAT1: alpha tubulin acetyltransferase 1; ATG: autophagy-related; BECN1: beclin 1; CQ: chloroquine; FBS: fetal bovine serum; GST: glutathione S-transferase; H4K16ac: histone H4 lysine 16 acetylation; HASMCs: human aortic smooth muscle cells; HBSS: Hank’s buffered salt solution; HDAC6: histone deacetylase 6; hMOF: human males absent on the first; IP: immunoprecipitation; KAT2A/GCN5: lysine acetyltransferase 2A; Lacta: lactacystin; LIR: LC3-interaction region; MAP1LC3: microtubule associated protein 1 light chain 3; MEFs: mouse embryonic fibroblasts; MTOC: microtubule-organizing center; PE: phosphatidylethanolamine; PtdIns3K: class III phosphatidylinositol 3-kinase; RUNX2: runt-related transcription factor 2; SIRT1: sirtuin 1; SIRT2: sirtuin 2; SQSTM1/p62: sequestosome 1; ULK1: unc-51 like autophagy activating kinase 1; VSMCs: vascular smooth muscle cells; WT: wild-type.

巨自噬/自噬是大分子和细胞器降解的基本过程，在基础水平上组成型发生，并在应激反应中上调。然而，自噬是否调节血管平滑肌细胞 (VSMCs) 迁移中的蛋白质乙酰化和微管稳定性仍然未知。在这里，我们证明组蛋白乙酰转移酶 KAT2A/GCN5（赖氨酸乙酰转移酶 2）通过保守的 LC3 相互作用区（LIR）域直接结合自噬体蛋白 MAP1LC3/LC3（微管相关蛋白 1 轻链 3）。这种相互作用是自噬体中 KAT2A 螯合和溶酶体酸水解酶降解所必需的。自噬的抑制导致 KAT2A 积累。KAT2A 作为乙酰转移酶起作用以增加 TUBA/α-微管蛋白乙酰化，促进微管聚合和稳定性，最终抑制细胞定向迁移。我们的研究结果表明，TUBA 的去乙酰化和通过 KAT2A 的选择性自噬降解扰乱微管稳定性对于自噬促进 VSMC 迁移至关重要。

缩写：ACTB：肌动蛋白β；ATAT1：α微管蛋白乙酰转移酶1；ATG：自噬相关；BECN1: beclin 1; CQ：氯喹；FBS：胎牛血清；GST：谷胱甘肽S-转移酶；H4K16ac：组蛋白 H4 赖氨酸 16 乙酰化；HASMCs：人主动脉平滑肌细胞；HBSS：汉克缓冲盐溶液；HDAC6：组蛋白脱乙酰酶 6；hMOF：第一次缺席的人类男性；IP：免疫沉淀；KAT2A/GCN5：赖氨酸乙酰转移酶 2A；乳酸：lactacystin；LIR：LC3-相互作用区；MAP1LC3：微管相关蛋白1轻链3；MEFs：小鼠胚胎成纤维细胞；MTOC：微管组织中心；PE：磷脂酰乙醇胺；PtdIns3K：III类磷脂酰肌醇3-激酶；RUNX2：runt相关转录因子2；SIRT1：sirtuin 1；SIRT2：sirtuin 2；SQSTM1/p62：sequestosome 1；ULK1：unc-51 类似自噬激活激酶 1；VSMC：血管平滑肌细胞；WT：野生型。