CAREER: The Effects of Liquid-Liquid Phase Separation on Ubiquilin Chaperone and Triage Activity

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。作为对细胞压力的响应，一些蛋白质通过一种名为液-液相分离(LLPs)的过程形成液滴，但LLPs对蛋白质活性的具体影响尚不清楚。其他蛋白质，被称为伴侣蛋白，具有缓解细胞压力的作用。该项目专注于一种名为泛素蛋白的蛋白质家族，该家族被认为是伴侣。Ubiquilins可以承受LLP，并通过防止形成有毒蛋白质聚集体来缓解细胞压力。该项目的目标是了解LLP如何影响Ubiquilins的能力，帮助蛋白质插入细胞膜或降解无法正确插入的蛋白质，这些作用对于防止有毒蛋白质聚集和其他形式的细胞应激至关重要。该研究项目与针对寄养儿童和托莱多公立学校(TPS)学生的三项关键外联活动密切结合。首先，与卢卡斯县儿童服务和TPS合作，将在Elevate夏令营举办科学日活动，为包括寄养青年在内的高危青年提供安全的夏季环境。露营者将了解STEM职业生涯，并进行基本的有限合伙人实验。其次，TPS高中生将到托莱多大学进行实地考察，参观实验室，揭开大学录取过程的神秘面纱，并了解STEM研究机会。第三，TPS学生和寄养青少年将在暑期研究实习中接受指导。这些外展活动将提高科学素养，改善STEM教育，并促进寄养青年和TPS学生充分参与STEM领域。美国救援计划的资金被用来支持这位早期职业调查员在他职业生涯的关键阶段。人类有三个广泛表达的Ubiqulin类比：Ubqln1，Ubqln2和Ubqln4。泛素已被证明可以与未插入的膜蛋白结合，并为有效的膜插入提供额外的机会。泛素还可以与泛素-蛋白酶体系统相互作用，促进客户蛋白质的降解。Ubqln2已被证明经历LLPs，但LLPs如何影响Ubqln2活性尚不清楚。这个项目的重点是确定LLP如何影响Ubiquilins对未插入的膜蛋白进行伴侣和分类的能力。该项目的目标是：(1)确定LLP如何影响泛素蛋白促进客户蛋白质泛素化和降解的能力，以及(2)确定LLP如何影响Ubiquilin与膜蛋白结合的能力，并促进它们插入脂质双层。该项目的完成将有助于首席研究人员了解有限合伙人对Ubiqulin活动的功能意义的长期目标。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). In response to cellular stress, some proteins form liquid-like droplets by a process called Liquid-Liquid Phase Separation (LLPS), but the specific effects of LLPS on protein activity are poorly understood. Other proteins, referred to as chaperones, have the role of mitigating cellular stress. This project focuses on a family of proteins called Ubiquilins that are considered chaperones. Ubiquilins can undergo LLPS and mitigate cellular stress by preventing the formation of toxic protein aggregates. The goal of this project is to understand how LLPS affects the ability of Ubiquilins to either assist proteins to insert into the cell membrane or degrade proteins that cannot properly insert, roles that are essential to prevent the accumulation of toxic protein aggregates and other forms of cell stress. The research project is intimately integrated with three key outreach activities targeted to children in foster care and students at Toledo Public Schools (TPS). First, in partnership with Lucas County Children Services and TPS, there will be science day at Elevate Summer Camp, which provides a safe summer environment for at risk youth, including foster youth. Campers will learn about STEM careers and conduct basic LLPS experiments. Second, TPS high school students will do a field trip to the University of Toledo to tour laboratories, demystify the college admission process, and learn about STEM research opportunities. Third, TPS students and foster youth will be mentored in a summer research internship. These outreach activities will increase scientific literacy, improve STEM education, and promote the full participation of foster youth and TPS students in STEM fields. American Rescue Plan funding is used to support this early career investigator at a critical stage in his career.Humans have three broadly expressed Ubiquilin paralogs: Ubqln1, Ubqln2, and Ubqln4. Ubiquilins have been shown to bind to uninserted membrane proteins and provide additional opportunities for productive membrane insertion. Ubiquilins can also interact with the Ubiquitin-Proteasome System to facilitate client protein degradation. Ubqln2 has been shown to undergo LLPS, but how LLPS affects Ubqln2 activity is unknown. This project focuses on determining how LLPS affects the ability of Ubiquilins to chaperone and triage uninserted membrane proteins. The project’s goals are to: (1) determine how LLPS affects the ability of Ubiquilins to facilitate client protein ubiquitination and degradation and (2) determine how LLPS affects the ability of Ubiquilins to bind membrane proteins and facilitate their insertion into the lipid bilayer. Completion of this project will facilitate the principal investigator’s long-term goal of understanding the functional significance of LLPS on Ubiquilin activity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.