Supporting data for supplemental figures.

G proteins (Gα and Gβγ subtypes) drive adenylyl cyclase type 5 (AC5) synthesis of cAMP in striatal neurons, which is essential for motor coordination. KCTD5 directly interacts with Gβγ to delimit signaling events, yet downstream impact of KCTD5 in striatal circuits is not known. Here, generation of a conditional Kctd5 knockout mouse identified that loss of striatal KCTD5 leads to a dystonic phenotype, coordination deficits, and skewed transitions between behavioral syllables. 2-photon imaging of a cAMP biosensor revealed electrically evoked dopaminergic responses were significantly augmented in the absence of KCTD5 in striatal circuits. cAMP sensitization was rescued in situ by expression of a Gβγ-scavenging nanobody and motor deficits were partially rescued in vivo by pharmacological antagonism of the indirect striatal cAMP pathway. Therefore, KCTD5 acts as a brake on cAMP signaling in striatal neurons important for tuning dopaminergic signaling and motor coordination.G蛋白（G proteins）的Gα和Gβγ亚型可介导纹状体神经元内5型腺苷酸环化酶（AC5）合成环磷酸腺苷（cAMP），该过程对运动协调至关重要。KCTD5可直接与Gβγ结合以限定信号转导事件的范围，但目前对于KCTD5在纹状体环路中的下游调控效应仍不明确。本研究通过构建条件性Kctd5基因敲除小鼠，发现纹状体KCTD5缺失会引发肌张力障碍表型、协调功能障碍以及行为音节间的转换失衡。借助cAMP生物传感器（cAMP biosensor）的双光子成像（2-photon imaging）实验显示，纹状体环路中KCTD5缺失可显著增强电诱发多巴胺能反应。原位实验中，表达Gβγ清除型纳米抗体（Gβγ-scavenging nanobody）可挽救cAMP敏化现象；活体实验中，通过药理学拮抗纹状体间接通路的cAMP信号途径可部分改善运动功能缺陷。综上，KCTD5可作为纹状体神经元内cAMP信号通路的负调控因子，在调控多巴胺能信号转导与运动协调过程中发挥关键作用。