RESUMO
Sin1 is a substrate-binding subunit of target of rapamycin complex 2 (TORC2), an evolutionarily conserved protein kinase complex. In fission yeast, Sin1 has also been identified as a protein that interacts with Spc1 (also known as Sty1) in the stress-activated protein kinase (SAPK) pathway. Therefore, this study examined the relationship between TORC2 and Spc1 signaling. We found that the common docking (CD) domain of Spc1 interacts with a cluster of basic amino acid residues in Sin1. Although diminished TORC2 activity in the absence of the functional Spc1 cascade suggests positive regulation of TORC2 by Spc1, such regulation appears to be independent of the Sin1-Spc1 interaction. Hyperosmotic stress transiently inhibits TORC2, and its swift recovery is dependent on Spc1, the transcription factor Atf1, and the glycelrol-3-phosphate dehydrogenase Gpd1, whose expression is induced upon osmostress by the Spc1-Atf1 pathway. Thus, cellular adaptation to osmostress seems important for TORC2 reactivation, though Spc1 and Atf1 contribute to TORC2 activation also in the absence of osmostress. These results indicate coordinated actions of the SAPK and TORC2 pathways, both of which are essential for fission yeast cells to survive environmental stress.
Assuntos
Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Fator 1 Ativador da Transcrição/genética , Fator 1 Ativador da Transcrição/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Alvo Mecanístico do Complexo 2 de Rapamicina/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Fosforilação , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologiaRESUMO
Morphological abnormalities of blood cells are the typical characteristics of myelodysplastic syndromes (MDS). Recently, the usefulness of multiparameter automatic hematology analyzer XE-2100 for detecting neutrophil dysplasia has been reported by using parameters of NEUT-X and NEUT-Y, reflecting neutrophil cytoplasmic granularity and the cellular content of nucleic acid and protein, respectively. We evaluated the utility of these parameters by analyzing the blood samples of fifty MDS patients consulting Kakogawa West Municipal Hospital between Jan, 2010 and Jun, 2014, as well as 100 persons undergoing medical examinations during the same period as controls. Neutrophil granulation level was classified as normal, hypo-granular, or agranular under microscopic observation, and degranulation index was calculated using the following formula. The relationship between NEUT-X, NEUT-Y values and degranulation index was studied as below. Degranulation index = agranular (%) x 2+ hypo-granular (%) x 1 + normal (%) x 0 Neut-X values of MDS patients were 1,350 (mean), 1,345 (median), and NEUT-Y values, 430 (mean) and 432 (median). The NEUT-X and NEUT-Y values of control patients were 1,350, 1,349, 446 and 445, respectively. Correlation efficiency between degranulation index and NEUT-X or NEUT-Y were r = 0.62 or 0.52, respectively. Relationship between NEUT-X and NEUT-Y for all patients was r = 0.90. All the 10 patients showing NEUT-X lower than 1,315 and NEUT-Y lower than 400 simultaneously were MDS. Hence, we conclude that NEUT-X and NEUT-Y information is useful for quantitative evaluation of neutrophil morphological abnormalities.