RESUMO
Fujioka et al. (2020) uncovered liquid-liquid phase separation of the PAS, a key driver of autophagosome formation in yeast. Moreover, the authors demonstrated that liquid-like PAS controls autophagic kinase activation and is itself regulated by the phosphorylation status of its constituents.
Assuntos
Autofagia , Proteínas de Saccharomyces cerevisiae , Autofagossomos , Proteínas Relacionadas à Autofagia , Saccharomyces cerevisiaeRESUMO
Hereditary sensory and autonomic neuropathy 9 (HSAN9) is a rare fatal neurological disease caused by mis- and nonsense mutations in the gene encoding for Tectonin ß-propeller repeat containing protein 2 (TECPR2). While TECPR2 is required for lysosomal consumption of autophagosomes and ER-to-Golgi transport, it remains elusive how exactly TECPR2 is involved in autophagy and secretion and what downstream sequels arise from defective TECPR2 due to its involvement in these processes. To address these questions, we determine molecular consequences of TECPR2 deficiency along the secretory pathway. By employing spatial proteomics, we describe pronounced changes with numerous proteins important for neuronal function being affected in their intracellular transport. Moreover, we provide evidence that TECPR2's interaction with the early secretory pathway is not restricted to COPII carriers. Collectively, our systematic profiling of a HSAN9 cell model points to specific trafficking and sorting defects which might precede autophagy dysfunction upon TECPR2 deficiency.
Assuntos
Proteômica , Via Secretória , Autofagossomos , Autofagia/genética , Complexo de Golgi , Transporte Proteico , Proteínas de Transporte/metabolismo , Proteínas do Tecido Nervoso/metabolismoRESUMO
HECT-E3 ligases play an essential role in catalyzing the transfer of ubiquitin to protein substrates. The noncatalytic roles of HECT-E3 ligases in cells are unknown. Here, we report that a HECT-E3 ligase, HACE1, functions as an adaptor independent of its E3 ligase activity. We identified Spindlin-1, a histone reader, as a new HACE1-associated protein. Interestingly, we found that HACE1 promotes Spindlin-1 degradation via the proteasome in an ubiquitination-independent manner. Functionally, we demonstrated that the loss of HACE1 results in weak cell-cell adhesion due to Spindlin-1-mediated accumulation of GDNF, a negative regulator of cell adhesion. Together, our data suggest that HACE1 acts as a molecular adaptor and plays an important noncatalytic role in presenting selected substrates directly to the proteasome for degradation.
Assuntos
Adesão Celular/genética , Proteínas de Ciclo Celular/genética , Fator Neurotrófico Derivado de Linhagem de Célula Glial/genética , Proteínas Associadas aos Microtúbulos/genética , Fosfoproteínas/genética , Processamento de Proteína Pós-Traducional , Ubiquitina-Proteína Ligases/genética , Comunicação Celular , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Células HEK293 , Humanos , Células MCF-7 , Proteínas Associadas aos Microtúbulos/metabolismo , Fosfoproteínas/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ubiquitina-Proteína Ligases/antagonistas & inibidores , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
We present a new method for splitting of operators in the three-dimensional finite difference split-step nonparaxial beam propagation method. The method increases the accuracy and the efficiency in terms of speed and memory requirements for three-dimensional wide-angle beam propagation. It also makes the application of the perfectly matched layer (PML) boundary condition very simple.