DEPDC5
Domain
The DEP domain mediates the interaction with KLHL22.
Function
As a component of the GATOR1 complex functions as an inhibitor of the amino acid-sensing branch of the mTORC1 pathway (PubMed:23723238, PubMed:25457612, PubMed:29590090, PubMed:29769719, PubMed:31548394, PubMed:35338845). In response to amino acid depletion, the GATOR1 complex has GTPase activating protein (GAP) activity and strongly increases GTP hydrolysis by RagA/RRAGA (or RagB/RRAGB) within heterodimeric Rag complexes, thereby turning them into their inactive GDP-bound form, releasing mTORC1 from lysosomal surface and inhibiting mTORC1 signaling (PubMed:23723238, PubMed:25457612, PubMed:29590090, PubMed:29769719, PubMed:35338845). In the presence of abundant amino acids, the GATOR1 complex is negatively regulated by GATOR2, the other GATOR subcomplex, in this amino acid-sensing branch of the TORC1 pathway (PubMed:23723238, PubMed:25457612, PubMed:29769719). Within the GATOR1 complex, DEPDC5 mediates direct interaction with the nucleotide-binding pocket of small GTPases Rag (RagA/RRAGA, RagB/RRAGB, RagC/RRAGC and/or RagD/RRAGD) and coordinates their nucleotide loading states by promoting RagA/RRAGA or RagB/RRAGB into their GDP-binding state and RagC/RRAGC or RagD/RRAGD into their GTP-binding state (PubMed:29590090, PubMed:35338845). However, it does not execute the GAP activity, which is mediated by NPRL2 (PubMed:29590090).
Involvement in disease
Epilepsy, familial focal, with variable foci 1
FFEVF1
An autosomal dominant form of epilepsy characterized by focal seizures arising from different cortical regions in different family members. Many patients have an aura and show automatisms during the seizures, whereas others may have nocturnal seizures. There is often secondary generalization. Some patients show abnormal interictal EEG, and some patients may have intellectual disability or autism spectrum disorders. Seizure onset usually occurs in the first or second decades, although later onset has been reported, and there is phenotypic variability within families. Penetrance of the disorder is incomplete.
None
The disease is caused by variants affecting the gene represented in this entry.
Developmental and epileptic encephalopathy 111
DEE111
A form of epileptic encephalopathy, a heterogeneous group of early-onset epilepsies characterized by refractory seizures, neurodevelopmental impairment, and poor prognosis. Development is normal prior to seizure onset, after which cognitive and motor delays become apparent. DEE111 is an autosomal recessive form characterized by the onset of seizures in the first days, months, or years of life. Brain imaging shows frontal, parietal, and perisylvian polymicrogyria, dysmorphic basal ganglia and corpus callosum, and hypoplastic pons. Death in early childhood may occur.
None
The disease is caused by variants affecting the gene represented in this entry.
Inactivating mutations and truncating deletions in the genes encoding GATOR1 proteins, including DEPDC5, are detected in glioblastoma and ovarian tumors and are associated with loss of heterozygosity events. Inactivation of GATOR1 proteins promotes constitutive localization of mTORC1 to the lysosomal membrane and blocks mTORC1 inactivation following amino acid withdrawal (PubMed:23723238).
Post-translational modifications
Phosphorylation at Ser-1002 and Ser-1530 by AKT1 and PIM1 inhibit the activity of DEPDC5, releasing inhibition of the mTORC1 pathway.
Ubiquitinated (PubMed:29769719). Amino acid-induced 'Lys-48'-linked polyubiquitination of DEPDC5 by the BCR(KLHL22) ubiquitin ligase complex leads to DEPDC5 proteasomal degradation and inhibition of the GATOR1 complex (PubMed:29769719). Ubiquitination may occur at multiple lysines (PubMed:29769719).
Sequence Similarities
Belongs to the IML1 family.
Tissue Specificity
Expressed in developing and adult brain.
Cellular localization
- Lysosome membrane
- Cytoplasm
- Cytosol
- Cytoplasm
- Perinuclear region
- Localization to lysosomes is mediated by the KICSTOR complex and is amino acid-independent.
Alternative names
KIAA0645, DEPDC5, GATOR1 complex protein DEPDC5, DEP domain-containing protein 5