RESUMO
Macroautophagy/autophagy involves the formation of an autophagosome, a double-membrane vesicle that delivers sequestered cytoplasmic cargo to lysosomes for degradation and recycling. Closely related, endocytosis mediates the sorting and transport of cargo throughout the cell, and both processes are important for cellular homeostasis. However, how endocytic proteins functionally intersect with autophagy is not clear. Mutations in the DAF-2/insulin-like IGF-1 (INSR) receptor at the permissive temperature result in a small increase in GFP::LGG-1 foci, i.e. autophagosomes, but a large increase at the nonpermissive temperature, allowing us to control the level of autophagy. In a RNAi screen for endocytic genes that alter the expression of GFP::LGG-1 in daf-2 mutants, we identified RAB-10, a small GTPase that regulates basolateral endocytosis. Loss of rab-10 in daf-2 mutants results in more GFP::LGG-1-positive foci at the permissive, but less GFP::LGG-1 or SQST-1::GFP foci at the nonpermissive temperature. As previously reported, loss of rab-10 alone resulted in an increase of GFP:LGG-1 foci. Exposure of rab-10 mutant animals to chloroquine, a known inhibitor of autophagic flux, failed to increase the number of GFP::LGG-1 foci. Moreover, colocalization between LMP-1::tagRFP and GFP::LGG-1 (the lysosome and autophagosome reporters) was decreased in daf-2; rab-10 dauers at the nonpermissive temperature. Intriguingly, RAB-10 was required to maintain the normal size of GFP::ATG-9-positive structures in daf-2 mutants at both the permissive and nonpermissive temperature. Finally, we found that RAB-10 GTPase cycling was required to control the size of GFP::ATG-9 foci. Collectively, our data support a model where rab-10 controls autophagic flux by regulating autophagosome formation and maturation.
Assuntos
Proteínas Relacionadas à Autofagia/metabolismo , Autofagia/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/fisiologia , Endossomos/metabolismo , Proteínas de Membrana/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Proteínas rab de Ligação ao GTP/fisiologia , Animais , Animais Geneticamente Modificados , Autofagossomos/metabolismo , Caenorhabditis elegans , Endocitose/genética , Endossomos/genética , Lisossomos/genética , Lisossomos/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Transporte Proteico/genéticaRESUMO
The importance in resuscitation treatment of the measurement of air ways flow resistance and compliance is stressed. In this regard, attention is paid to the possibility of utilizing the automatic respiratory (recording the mouth pressure curve) as an authentic measuring apparatus for these factors. Research into mechanical models and real patients also points to the possibility (seemingly not reported up to now) of measuring expiratory resistance independently and of highlighting air-trapping phenomena.
