BECN1 (beclin 1) is a member of the nucleation complex and considered crucial for induction of macroautophagy/autophagy, leading to the formation and ultimate degradation of autophagosomes. We found that in human B lymphoblastoid cell lines (LCLs) deficient of BECN1 (BECN1-KO), autophagosome formation was intact and autophagic flux could be induced upon nutrient starvation or MTOR inhibition. Remarkably, autophagosomal cargo differed significantly between BECN1-KO and control (CTRL) LCLs,...

Focal cortical dysplasia type II (FCDII), a major cause of paediatric drug-resistant focal epilepsy, results from brain somatic variants in mTOR pathway genes, including germline and somatic second-hit loss-of-function variants in the mTOR repressor DEPDC5. Here, we present a proof-of-concept model of DEPDC5 two-hit inactivation mosaicism using patient-derived human cortical organoids (hCOs). Mosaic hCOs displayed increased mTOR activity that was rescued by the mTOR inhibitor rapamycin. Mosaic...

2025 marked the 20th anniversary of a discovery that reshaped the understanding of nutrient signaling. How nutrients, specifically amino acids, impinge on the target of rapamycin complex 1 (TORC1), a eukaryotic protein kinase complex and growth regulator, long remained a mystery. Identification of the EGO complex in Saccharomyces cerevisiae provided the functional link between Rag GTPases and TORC1 reactivation in a nutrient-responsive context, revealing a vacuolar membrane-based growth control...

The greater amberjack Seriola dumerili is a promising aquaculture species in the Mediterranean Sea. However, first generation (F1) hatchery-produced individuals exhibit reproductive dysfunctions when reared in tanks or in cages. As part of a broader investigation into the impacts of captivity, we compared the pituitary transcriptomes of wild and F1 greater amberjack during spermatogenesis. Wild males (WILD group, n = 4) displayed normal testicular development; among F1 males, some had normal...

The mechanistic target of rapamycin complex 1 (mTORC1) integrates growth factor (GF) and nutrient signals to stimulate anabolic processes connected to cell growth and inhibit catabolic processes such as autophagy^(1,2). GF signalling through the tuberous sclerosis complex regulates the lysosomally localized small GTPase RAS homologue enriched in brain (RHEB)³. Direct binding of RHEB-GTP to the mTOR kinase subunit of mTORC1 allosterically activates the kinase by inducing a large-scale...

TELO2-TTI1-TTI2 (TTT) and R2TP are multi-subunit chaperones that cooperate with HSP90 to assemble matured complexes of the PIKK family of kinases, including mTOR complex 1 (mTORC1). WAC, a protein previously implicated in transcription, H2B ubiquitination, and autophagy, was recently identified as a regulator of mTORC1 in response to glucose and glutamine availability, acting in concert with R2TP and TTT. However, the molecular basis of the interactions of WAC with R2TP and TTT and their role in...

DEP-domain containing-5 (DEPDC5) is part of the GATOR1 complex that inhibits the mechanistic target of rapamycin complex-1 (mTORC1). Loss-of-function mutations in human DEPDC5 are the most common cause of lesional or non-lesional focal epilepsies associated with mTOR hyperactivation. Depdc5 silencing in mature neurons leads to excitation/inhibition imbalance and increased excitatory synapse strength. However, no link exists between mTORC1 hyperactivity and the increased activity of glutamatergic...

Cells experience oxidative stress and widespread cellular damage during stress-induced premature senescence (SIPS). Senescent cells show an increase in lysosomal content, which may contribute to mitigating cellular damage by promoting autophagy. This study investigates the dynamics of lysosomal quality control in human dermal fibroblasts (HDF), specifically examining lysosomal signaling pathways during oxidative stress-induced SIPS. Our results reveal distinct signaling responses between the...

Focal cortical dysplasia type II (FCDII) is a cortical malformation causing refractory epilepsy. FCDII arises from developmental somatic activating mutations in mTOR pathway genes, leading to focal cortical dyslamination and abnormal cytomegalic cells. Which cell types carry pathogenic mutations and how they affect cell-type-specific transcriptional programs remain unknown. In the present study, we combined several single-nucleus genotyping and transcriptomics approaches with spatial resolution...

Ependymal cells are multiciliated glial cells lining the ventricles of the mammalian brain. Their differentiation from progenitor cells involves cell enlargement and progresses through centriole amplification phases and ciliogenesis. These phases are accompanied by the sharp up-regulation of mTOR Complex 1 activity (mTORC1), a master regulator of macromolecule biosynthesis and cell growth, whose function in ependymal cell differentiation is unknown. We demonstrate that mTORC1 inhibition by...

Lesional focal epilepsy (LFE) is a common and severe seizure disorder caused by epileptogenic lesions, including malformations of cortical development (MCD) and low-grade epilepsy-associated tumors (LEAT). Understanding the genetic etiology of these lesions can inform medical and surgical treatment. We conducted a somatic variant enrichment mega-analysis in brain tissue from 1386 individuals who underwent epilepsy surgery, including 599 previously unpublished individuals with ultra-deep ( >...

Mechanistic target of rapamycin complex 1 (mTORC1), which consists of mTOR, Raptor, and mLST8, receives signaling inputs from growth factor signals and nutrients. These signals are mediated by the Rheb and Rag small GTPases, respectively, which activate mTORC1 on the cytosolic face of the lysosome membrane. We biochemically reconstituted the activation of mTORC1 on membranes by physiological submicromolar concentrations of Rheb, Rags, and Ragulator. We determined the cryo-EM structure and found...