Dynamic early recruitment of GAK-Hsc70 regulates coated pit maturation

• 成果类型: Article
• 署名作者: He, Zhangping; Zuo, Peiyao; Xu, Peiliu; Yuan, Haozhi; Bhave, Madhura; Wei, Xiangying; Yang, Ziyan; Han, Lu; Schmid, Sandra L.; Chen, Zhiming
• 署名单位: University of South China; University of South China; University of Texas System; University of Texas Southwestern Medical Center; Chan Zuckerberg Initiative (CZI); Minjiang University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12452
• DOI: 10.1073/pnas.2503738122
• 发表日期: 2025-06-03
• 关键词: endocytic accessory proteins; g-associated kinase; functional-characterization; clathrin lattices; multiple roles; auxilin; vesicles; mechanism; binding; hsc70

摘要

Clathrin-mediated endocytosis (CME) begins with the assembly of clathrin onto the plasma membrane. These structures grow and stabilize to form clathrin-coated pits (CCPs), which invaginate and accumulate cargo. Finally, through membrane fission, CCPs detach to form clathrin-coated vesicles (CCVs). Mechanisms governing the transition of CCPs from flat-to-curved structures have been a matter of debate. GAK and its chaperone protein, Hsc70, are well known to mediate clathrin release from CCVs, and several studies have observed a late burst of GAK recruitment as CCVs form. Other studies have proposed that early recruitment of GAK-Hsc70 could function to provide the necessary energy source to remodel nascent flat clathrin lattices, replacing hexagons with pentagons and enabling a gain of curvature and invagination of the growing CCP; however, direct functional evidence is lacking. Here, we show that GAK knockdown inhibits CCP stabilization and invagination. Furthermore, mutations in the J domain of GAK that abolish Hsc70 recruitment to and activation at CCPs lead to the accumulation of GAK at CCPs, hinder CCP stabilization and invagination, and result in a striking increase in the proportion of highly transient, abortive CCPs. These findings support the hypothesis that GAK-Hsc70 promotes the turnover and remodeling of nascent clathrin assemblies required for curvature development during CME.