Vacuolar H+-ATPase–dependent (V-ATPase–dependent) functions are critical for neural proteostasis and are involved in neurodegeneration and brain tumorigenesis. We identified a patient with fulminant neurodegeneration of the developing brain carrying a de novo splice site variant in ATP6AP2 encoding an accessory protein of the V-ATPase. Functional studies of induced pluripotent stem cell–derived (iPSC-derived) neurons from this patient revealed reduced spontaneous activity and severe deficiency in lysosomal acidification and protein degradation leading to neuronal cell death. These deficiencies could be rescued by expression of full-length ATP6AP2. Conditional deletion of Atp6ap2 in developing mouse brain impaired V-ATPase–dependent functions, causing impaired neural stem cell self-renewal, premature neuronal differentiation, and apoptosis resulting in degeneration of nearly the entire cortex. In vitro studies revealed that ATP6AP2 deficiency decreases V-ATPase membrane assembly and increases endosomal-lysosomal fusion. We conclude that ATP6AP2 is a key mediator of V-ATPase–dependent signaling and protein degradation in the developing human central nervous system.
Takuo Hirose, Alfredo Cabrera-Socorro, David Chitayat, Thomas Lemonnier, Olivier Féraud, Carmen Cifuentes-Diaz, Nicolas Gervasi, Cedric Mombereau, Tanay Ghosh, Loredana Stoica, Jeanne d’Arc Al Bacha, Hiroshi Yamada, Marcel A. Lauterbach, Marc Guillon, Kiriko Kaneko, Joy W. Norris, Komudi Siriwardena, Susan Blasér, Jérémie Teillon, Roberto Mendoza-Londono, Marion Russeau, Julien Hadoux, Sadayoshi Ito, Pierre Corvol, Maria G. Matheus, Kenton R. Holden, Kohji Takei, Valentina Emiliani, Annelise Bennaceur-Griscelli, Charles E. Schwartz, Genevieve Nguyen, Matthias Groszer
Usage data is cumulative from April 2019 through January 2020.
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.