Feng Wei, Wang Li, Bogomolovas Julius, Zhang Zengming, Huang Titania, Chang Chien-Wei, Shain Abraham, Gu Yusu, Cho Yoshitake, Zhou Xiaohai, Chen Ju
Division of Cardiovascular Medicine, Department of Medicine University of California San Diego La Jolla CA USA.
Division of Biological Sciences University of California San Diego La Jolla CA USA.
J Am Heart Assoc. 2025 Apr;14(7):e039464. doi: 10.1161/JAHA.124.039464. Epub 2025 Mar 26.
ALPK3 (α protein kinase 3) is an atypical kinase highly expressed in human and murine hearts. Biallelic loss-of-function mutations in ALPK3 lead to pediatric cardiomyopathy. The specific stages at which ALPK3 is essential for cardiac function and the mechanisms by which it regulates cardiac function require further exploration.
We generated ALPK3 global knockout and inducible cardiac-specific knockout mice. We performed time-course physiological and morphological assessments to determine ALPK3's role in neonatal and adult hearts. We also generated an -3xFLAG-HA knock-in mouse model to determine endogenous ALPK3 localization. To investigate mechanisms of ALPK3 regulation, we performed biochemical assays and RNA sequencing experiments in global knockout mice. ALPK3 is critical for both neonatal and adult cardiac function. Loss of ALPK3 at germline and adult stages leads to dilated cardiomyopathy. Approximately 75% of germline ALPK3 mice die within 1 month, while surviving mutant mice develop dilated cardiomyopathy that transitions to left ventricular hypertrophy, mirroring clinical manifestations in human patients with biallelic ALPK3 mutations. We found that ALPK3 localizes to the M-band in both neonatal and adult cardiomyocytes and interacts with muscle RING-finger proteins, which may regulate thick filament protein turnover.
Our study highlights the necessity of ALPK3 in neonatal and adult cardiac function. Our data support a model in which ALPK3 serves as a scaffold protein to recruit machineries essential for regulating thick filament protein turnover.
ALPK3（α蛋白激酶3）是一种在人和小鼠心脏中高度表达的非典型激酶。ALPK3的双等位基因功能丧失突变会导致小儿心肌病。ALPK3对心脏功能至关重要的具体阶段及其调节心脏功能的机制需要进一步探索。
我们构建了ALPK3全基因敲除和诱导型心脏特异性敲除小鼠。我们进行了时间进程的生理和形态学评估，以确定ALPK3在新生和成年心脏中的作用。我们还构建了一个-3xFLAG-HA敲入小鼠模型，以确定内源性ALPK3的定位。为了研究ALPK3的调节机制，我们在全基因敲除小鼠中进行了生化分析和RNA测序实验。ALPK3对新生和成年心脏功能都至关重要。在种系和成年阶段缺失ALPK3会导致扩张型心肌病。大约75%的种系ALPK3小鼠在1个月内死亡，而存活的突变小鼠会发展为扩张型心肌病，并转变为左心室肥厚，这与双等位基因ALPK3突变的人类患者的临床表现相似。我们发现，ALPK3在新生和成年心肌细胞中均定位于M带，并与肌肉环指蛋白相互作用，这可能调节粗肌丝蛋白的周转。
我们的研究强调了ALPK3在新生和成年心脏功能中的必要性。我们的数据支持一种模型，即ALPK3作为一种支架蛋白，募集调节粗肌丝蛋白周转所必需的机制。
