Structural insights into the substrate uptake and inhibition of the human creatine transporter (hCRT)

• 成果类型: Article
• 署名作者: Yuan, Xinyi; Yin, Jian; Liu, Chang; Chen, Xudong; Chen, Meiying; Wang, Yixue; Yang, Zi; Wang, Yue; Jiang, Li; Zhou, Niyun; Wang, Xiaojuan; Liu, Botong; Ma, Zhaoqi; Wang, Kaiyan; Li, Hongen; Zhang, Sensen; Shang, Yongfeng; Yang, Maojun
• 署名单位: Hangzhou Normal University; Hangzhou Normal University; Peking University; Tsinghua University; Tsinghua University; Capital Medical University; China Agricultural University; Air Force Medical University; Air Force Medical University; Chinese People's Liberation Army General Hospital
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11215
• DOI: 10.1073/pnas.2426135122
• 发表日期: 2025-09-09
• 关键词: gene slc6a8; functional-characterization; missense variants; deficiency; rat; expression; defect; brain; neurotransmitter; identification

摘要

Creatine plays a vital role in cellular energy production and adenosine triphosphate (ATP) homeostasis and has also been identified as a neurotransmitter in the mammalian brain. Creatine is transported into cells by the human creatine transporter Mutations in hCRT cause cerebral creatine deficiency syndrome 1, a neurological disorder marked by intellectual disability, speech delay, and seizures. Beyond its role in the brain and muscle, hCRT is highly expressed in metabolically active tumors. Many cancer cells, including colorectal cancer and glioblastoma, upregulate hCRT to sustain intracellular creatine levels and buffer ATP under energy stress. Pharmacological blockade of hCRT by RGX202 has been shown to impair tumor growth by disrupting energy homeostasis. Here, we report the high- resolution cryo- Electron Microscopy (cryo- EM) structures of human hCRT in three states: apo, creatine- bound, and RGX202- bound. hCRT adopts a canonical LeuT- fold with 12 transmembrane helices and two pseudosymmetric inverted repeats. Creatine is coordinated in the central substrate- binding site through interactions with transmembrane helices TM1, TM3, TM6, and TM8, while the inhibitor RGX202 occupies the same binding pocket, engaging in overlapping contacts that competitively block creatine access. Our structural and mechanistic findings clarify substrate recognition and inhibitory binding of hCRT, providing a molecular rationale for targeting hCRT in both inherited metabolic diseases and cancer therapy.