Mapping Interactome Networks of DNAJC11, a Novel Mitochondrial Protein Causing Neuromuscular Pathology in Mice

We previously identified DNAJC11,
a mitochondrial outer membrane
protein of unknown function, as a novel genetic cause in modeled neuromuscular
disease. To understand the physiological role of DNAJC11, we employed
a proteomic approach for the identification of the DNAJC11 interactome,
through the expression of DNAJC11-FLAG in HEK293FT cells and transgenic
mice. Our analysis confirmed known DNAJC11-interacting proteins including
members of the MICOS complex that organize mitochondrial cristae formation.
Moreover, we identified in both biological systems novel mitochondrial
interactions including VDACs that exchange metabolites across the
outer mitochondrial membrane. In HEK293FT cells, DNAJC11 preferentially
interacted with ribosomal subunits and chaperone proteins including
Hsp70 members, possibly correlating DNAJC11 with cotranslational folding
and import of mitochondrial proteins in metabolically active cells.
Instead, the DNAJC11 interactome in the mouse cerebrum was enriched
for synaptic proteins, supporting the importance of DNAJC11 in synapse
and neuronal integrity. Moreover, we demonstrated that the DUF3395
domain is critically involved in DNAJC11 protein–protein interactions,
while the J-domain determines its mitochondrial localization. Collectively,
these results provide a functional characterization for DNAJC11 domains,
while the identified interactome networks reveal an emerging role
of DNAJC11 in mitochondrial biogenesis and response to microenvironment
changes and requirements.

此前，我们已将DNAJC11鉴定为一种线粒体外膜蛋白，其功能尚不明确，并作为神经肌肉疾病新型遗传病因。为探究DNAJC11的生理作用，我们采用蛋白质组学方法，通过在HEK293FT细胞和转基因小鼠中表达DNAJC11-FLAG，对DNAJC11互作组进行了鉴定。我们的分析证实了已知与DNAJC11相互作用的蛋白，包括组织线粒体嵴形成的MICOS复合体成员。此外，在两种生物系统中，我们还发现了新的线粒体相互作用，包括跨越线粒体外膜交换代谢物的VDACs。在HEK293FT细胞中，DNAJC11优先与核糖体亚基和包括Hsp70成员在内的伴侣蛋白相互作用，这可能与DNAJC11与代谢活跃细胞中线粒体蛋白的共翻译折叠和导入相关。相反，小鼠大脑中的DNAJC11互作组富含突触蛋白，支持DNAJC11在突触和神经元完整性中的重要性。此外，我们证明DUF3395结构域在DNAJC11蛋白-蛋白相互作用中发挥关键作用，而J结构域则决定其线粒体定位。综合上述结果，对DNAJC11结构域的功能特征进行了描述，而所鉴定的互作网络揭示了DNAJC11在线粒体生物发生、对微环境变化和需求的响应中崭露头角的新角色。