Hematopoiesis is crucial for organismal health,and Drosophila serves as an effective genetic model due to conserved regulatory mechanisms with vertebrates.In larvae,hematopoiesis primarily occurs in the lymph gland,wh...Hematopoiesis is crucial for organismal health,and Drosophila serves as an effective genetic model due to conserved regulatory mechanisms with vertebrates.In larvae,hematopoiesis primarily occurs in the lymph gland,which contains distinct zones,including the cortical zone,intermediate zone,medullary zone,and posterior signaling center(PSC).Rab1 is vital for membrane trafficking and maintaining the localization of cell adhesion molecules,yet its role in hematopoietic homeostasis is not fully understood.This study investigates the effects of Rab1 dysfunction on β-integrin trafficking within circulating hemocytes and lymph gland cells.Rab1 impairment disrupts the endosomal trafficking of β-integrin,leading to its abnormal localization on cell membranes,which promotes lamellocyte differentiation and alters progenitor dynamics in circulating hemocytes and lymph glands,respectively.We also show that the mislocalization of β-integrin is dependent on the adhesion protein DE-cadherin.The reduction of β-integrin at cell boundaries in PSC cells leads to fewer PSC cells and lamellocyte differentiation.Furthermore,Rab1 regulates the trafficking of β-integrin via the Q-SNARE protein Syntaxin 17(Syx17).Our findings indicate that Rab1 and Syx17 regulate distinct trafficking pathways for β-integrin in different hematopoietic compartments and maintain hematopoietic homeostasis of Drosophila.展开更多
In eukaryotic cells,organelles in the secretory,lysosomal,and endocytic pathways actively exchange biological materials with each other through intracellular membrane trafficking,which is the process of transporting t...In eukaryotic cells,organelles in the secretory,lysosomal,and endocytic pathways actively exchange biological materials with each other through intracellular membrane trafficking,which is the process of transporting the cargo of proteins,lipids,and other molecules to appropriate compartments via transport vesicles or intermediates.These processes are strictly regulated by various small GTPases such as the RAS-like in rat brain(RAB)protein family,which is the largest subfamily of the RAS superfamily.Dysfunction of membrane trafficking affects tissue homeostasis and leads to a wide range of diseases,including neurological disorders and neurodegenerative diseases.Therefore,it is important to understand the physiological and pathological roles of RAB proteins in brain function.RAB35,a member of the RAB family,is an evolutionarily conserved protein in metazoans.A wide range of studies using cultured mammalian cells and model organisms have revealed that RAB35 mediates various processes such as cytokinesis,endocytic recycling,actin bundling,and cell migration.RAB35 is also involved in neurite outgrowth and turnover of synaptic vesicles.We generated brain-specific Rab35 knockout mice to study the physiological roles of RAB35 in brain development and function.These mice exhibited defects in anxiety-related behaviors and spatial memory.Strikingly,RAB35 is required for the precise positioning of pyramidal neurons during hippocampal development,and thereby for normal hippocampal lamination.In contrast,layer formation in the cerebral cortex occurred superficially,even in the absence of RAB35,suggesting a predominant role for RAB35 in hippocampal development rather than in cerebral cortex development.Recent studies have suggested an association between RAB35 and neurodegenerative diseases,including Parkinson's disease and Alzheimer's disease.In this review,we provide an overview of the current understanding of subcellular functions of RAB35.We also provide insights into the physiological role of RAB35 in mammalian brain development and function,and discuss the involvement of RAB35 dysfunction in neurodegenerative diseases.展开更多
Rab5 is a GTPase protein that is involved in intracellular membrane trafficking. It functions by binding to various effector proteins and regulating cellular responses, including the formation of transport vesicles an...Rab5 is a GTPase protein that is involved in intracellular membrane trafficking. It functions by binding to various effector proteins and regulating cellular responses, including the formation of transport vesicles and their fusion with the cellular membrane. Rab5 has been reported to play an important role in the development of the zebrafish embryo;however, its role in axonal regeneration in the central nervous system remains unclear. In this study, we established a zebrafish Mauthner cell model of axonal injury using single-cell electroporation and two-photon axotomy techniques. We found that overexpression of Rab5 in single Mauthner cells promoted marked axonal regeneration and increased the number of intra-axonal transport vesicles. In contrast, treatment of zebrafish larvae with the Rab kinase inhibitor CID-1067700markedly inhibited axonal regeneration in Mauthner cells. We also found that Rab5 activated phosphatidylinositol 3-kinase(PI3K) during axonal repair of Mauthner cells and promoted the recovery of zebrafish locomotor function. Additionally, rapamycin, an inhibitor of the mechanistic target of rapamycin downstream of PI3K, markedly hindered axonal regeneration. These findings suggest that Rab5 promotes the axonal regeneration of injured zebrafish Mauthner cells by activating the PI3K signaling pathway.展开更多
Background:The decreased slowly activating delayed rectifier K+current(IKs)is the molecular basis of arrhythmia caused by myocardial hypertrophy.The aim of this study was to investigate the mechanism of IKs down-regul...Background:The decreased slowly activating delayed rectifier K+current(IKs)is the molecular basis of arrhythmia caused by myocardial hypertrophy.The aim of this study was to investigate the mechanism of IKs down-regulation related to the channel number,as well as the regulation of channel number under pathological conditions.Methods:The HEK 293 cell co-transfected with KCNQ1/KCNE1 genes was cultured conventionally.After the cells incubated with angiotensin II(AngII)(24 h),AngII(72 h),bisindolylmaleimide I(Bis),brefeldin A and dynasore,the effect and relevant mechanism of long term incubation of AngII on the IKs tail current and KCNQ1 channel total protein were investigated by electrophysiology method and western blotting.In the experiment,the Bis,brefeldin A and dynasore could inhibit the protein kinase C(PKC)activity,the forward transport of KCNQ1 channel and the endocytosis of KCNQ1 channel,respectively.At last,the Rab GTPases 11(Rab11)dominant-negative mutant dsRed-Rab11/S25N was infected into the cells to investigate the effect and relevant mechanism of long term AngII incubation on the IKs tail current and KCNQ1 channel total protein.Results:Our results showed that the decreased IKs tail current and the KCNQ1 channel total protein caused by long term AngII incubation were attenuated by Bis treatment,which inhibited PKC activity.In addition,the inhibited IKs tail current and KCNQ1 channel total protein were also alleviated by brefeldin A and dynasore treatment.At last,the expression of Rab11 dominant-negative mutant dsRed-Rab11/S25N could weak the inhibition of IKs tail current and the KCNQ1 channel total protein caused by long term AngII incubation.Conclusion:The long term incubation of AngII inhibited the IKs tail current and KCNQ1 channel total protein was achieved by PKC activation and the disorder of the channel trafficking by Rab11.展开更多
BACKGROUND Ras-related protein Rab24,which belongs to the small GTPase family,plays a crucial role in regulating intracellular protein trafficking.Dysregulation of Rab24 has been recently identified in hepatocellular ...BACKGROUND Ras-related protein Rab24,which belongs to the small GTPase family,plays a crucial role in regulating intracellular protein trafficking.Dysregulation of Rab24 has been recently identified in hepatocellular carcinoma(HCC).However,its clinical significance and tumor related effects remain to be further clarified.AIM To explore the expression pattern of Rab24 and its role in HCC progression.METHODS The expression profile of Rab24 was tested in HCC tissues together with adjacent tissues from transcriptional,mRNA,and protein levels.The prognostic role of Rab24 in HCC was assessed by univariate and multivariate analyses.Clinical outcomes were evaluated by the Kaplan-Meier analysis and log-rank test.The effect of Rab24 on cell proliferation was tested through cellular experiments and xenograft experiments.RESULTS Rab24 expression was elevated in HCC tissues compared to adjacent liver tissues.High expression of Rab24 was significantly associated with larger tumor size and advanced tumor stage.Moreover,HCC patients with high Rab24 expression showed poorer overall survival,and Rab24 was identified as an independent prognosis factor according to multivariate analysis.By using overexpression and shRNA knockdown strategies in HCC cell lines,we found that Rab24 can promote HCC proliferation.Finally,we validated that silencing Rab24 significantly attenuated xenograft growth in vivo.CONCLUSION Our study demonstrated that high expression of Rab24 was significantly correlated with poorer prognosis of HCC patients,indicating the potential of Rab24 as a novel clinical biomarker and therapeutic target.展开更多
基金supported by the National Natural Science Foundation of China(32170484 and 32300384)the Fundamental Research Funds for the Central Universities(2572022DQ07 and 2572020AW04).
文摘Hematopoiesis is crucial for organismal health,and Drosophila serves as an effective genetic model due to conserved regulatory mechanisms with vertebrates.In larvae,hematopoiesis primarily occurs in the lymph gland,which contains distinct zones,including the cortical zone,intermediate zone,medullary zone,and posterior signaling center(PSC).Rab1 is vital for membrane trafficking and maintaining the localization of cell adhesion molecules,yet its role in hematopoietic homeostasis is not fully understood.This study investigates the effects of Rab1 dysfunction on β-integrin trafficking within circulating hemocytes and lymph gland cells.Rab1 impairment disrupts the endosomal trafficking of β-integrin,leading to its abnormal localization on cell membranes,which promotes lamellocyte differentiation and alters progenitor dynamics in circulating hemocytes and lymph glands,respectively.We also show that the mislocalization of β-integrin is dependent on the adhesion protein DE-cadherin.The reduction of β-integrin at cell boundaries in PSC cells leads to fewer PSC cells and lamellocyte differentiation.Furthermore,Rab1 regulates the trafficking of β-integrin via the Q-SNARE protein Syntaxin 17(Syx17).Our findings indicate that Rab1 and Syx17 regulate distinct trafficking pathways for β-integrin in different hematopoietic compartments and maintain hematopoietic homeostasis of Drosophila.
基金supported by the Japan Society for the Promotion of Science KAKENHI(grant Nos.23K05678 to IM,19H05711 and 20H00466 to KS)the Joint Research Program of Institute for Molecular and Cellular Regulation,Gunma University(to KS)。
文摘In eukaryotic cells,organelles in the secretory,lysosomal,and endocytic pathways actively exchange biological materials with each other through intracellular membrane trafficking,which is the process of transporting the cargo of proteins,lipids,and other molecules to appropriate compartments via transport vesicles or intermediates.These processes are strictly regulated by various small GTPases such as the RAS-like in rat brain(RAB)protein family,which is the largest subfamily of the RAS superfamily.Dysfunction of membrane trafficking affects tissue homeostasis and leads to a wide range of diseases,including neurological disorders and neurodegenerative diseases.Therefore,it is important to understand the physiological and pathological roles of RAB proteins in brain function.RAB35,a member of the RAB family,is an evolutionarily conserved protein in metazoans.A wide range of studies using cultured mammalian cells and model organisms have revealed that RAB35 mediates various processes such as cytokinesis,endocytic recycling,actin bundling,and cell migration.RAB35 is also involved in neurite outgrowth and turnover of synaptic vesicles.We generated brain-specific Rab35 knockout mice to study the physiological roles of RAB35 in brain development and function.These mice exhibited defects in anxiety-related behaviors and spatial memory.Strikingly,RAB35 is required for the precise positioning of pyramidal neurons during hippocampal development,and thereby for normal hippocampal lamination.In contrast,layer formation in the cerebral cortex occurred superficially,even in the absence of RAB35,suggesting a predominant role for RAB35 in hippocampal development rather than in cerebral cortex development.Recent studies have suggested an association between RAB35 and neurodegenerative diseases,including Parkinson's disease and Alzheimer's disease.In this review,we provide an overview of the current understanding of subcellular functions of RAB35.We also provide insights into the physiological role of RAB35 in mammalian brain development and function,and discuss the involvement of RAB35 dysfunction in neurodegenerative diseases.
基金supported by the Research Funds of the Center for Advanced Interdisciplinary Science and Biomedicine of IHM,No.QYZD20220002the National Natural Science Foundation of China,No.82071357a grant from the Ministry of Science and Technology of China,No.2019YFA0405600 (all to BH)。
文摘Rab5 is a GTPase protein that is involved in intracellular membrane trafficking. It functions by binding to various effector proteins and regulating cellular responses, including the formation of transport vesicles and their fusion with the cellular membrane. Rab5 has been reported to play an important role in the development of the zebrafish embryo;however, its role in axonal regeneration in the central nervous system remains unclear. In this study, we established a zebrafish Mauthner cell model of axonal injury using single-cell electroporation and two-photon axotomy techniques. We found that overexpression of Rab5 in single Mauthner cells promoted marked axonal regeneration and increased the number of intra-axonal transport vesicles. In contrast, treatment of zebrafish larvae with the Rab kinase inhibitor CID-1067700markedly inhibited axonal regeneration in Mauthner cells. We also found that Rab5 activated phosphatidylinositol 3-kinase(PI3K) during axonal repair of Mauthner cells and promoted the recovery of zebrafish locomotor function. Additionally, rapamycin, an inhibitor of the mechanistic target of rapamycin downstream of PI3K, markedly hindered axonal regeneration. These findings suggest that Rab5 promotes the axonal regeneration of injured zebrafish Mauthner cells by activating the PI3K signaling pathway.
基金supported by the National Natural Science Foundation of China(NSFC)Youth Project(No.82204397 and No.22203063).
文摘Background:The decreased slowly activating delayed rectifier K+current(IKs)is the molecular basis of arrhythmia caused by myocardial hypertrophy.The aim of this study was to investigate the mechanism of IKs down-regulation related to the channel number,as well as the regulation of channel number under pathological conditions.Methods:The HEK 293 cell co-transfected with KCNQ1/KCNE1 genes was cultured conventionally.After the cells incubated with angiotensin II(AngII)(24 h),AngII(72 h),bisindolylmaleimide I(Bis),brefeldin A and dynasore,the effect and relevant mechanism of long term incubation of AngII on the IKs tail current and KCNQ1 channel total protein were investigated by electrophysiology method and western blotting.In the experiment,the Bis,brefeldin A and dynasore could inhibit the protein kinase C(PKC)activity,the forward transport of KCNQ1 channel and the endocytosis of KCNQ1 channel,respectively.At last,the Rab GTPases 11(Rab11)dominant-negative mutant dsRed-Rab11/S25N was infected into the cells to investigate the effect and relevant mechanism of long term AngII incubation on the IKs tail current and KCNQ1 channel total protein.Results:Our results showed that the decreased IKs tail current and the KCNQ1 channel total protein caused by long term AngII incubation were attenuated by Bis treatment,which inhibited PKC activity.In addition,the inhibited IKs tail current and KCNQ1 channel total protein were also alleviated by brefeldin A and dynasore treatment.At last,the expression of Rab11 dominant-negative mutant dsRed-Rab11/S25N could weak the inhibition of IKs tail current and the KCNQ1 channel total protein caused by long term AngII incubation.Conclusion:The long term incubation of AngII inhibited the IKs tail current and KCNQ1 channel total protein was achieved by PKC activation and the disorder of the channel trafficking by Rab11.
文摘BACKGROUND Ras-related protein Rab24,which belongs to the small GTPase family,plays a crucial role in regulating intracellular protein trafficking.Dysregulation of Rab24 has been recently identified in hepatocellular carcinoma(HCC).However,its clinical significance and tumor related effects remain to be further clarified.AIM To explore the expression pattern of Rab24 and its role in HCC progression.METHODS The expression profile of Rab24 was tested in HCC tissues together with adjacent tissues from transcriptional,mRNA,and protein levels.The prognostic role of Rab24 in HCC was assessed by univariate and multivariate analyses.Clinical outcomes were evaluated by the Kaplan-Meier analysis and log-rank test.The effect of Rab24 on cell proliferation was tested through cellular experiments and xenograft experiments.RESULTS Rab24 expression was elevated in HCC tissues compared to adjacent liver tissues.High expression of Rab24 was significantly associated with larger tumor size and advanced tumor stage.Moreover,HCC patients with high Rab24 expression showed poorer overall survival,and Rab24 was identified as an independent prognosis factor according to multivariate analysis.By using overexpression and shRNA knockdown strategies in HCC cell lines,we found that Rab24 can promote HCC proliferation.Finally,we validated that silencing Rab24 significantly attenuated xenograft growth in vivo.CONCLUSION Our study demonstrated that high expression of Rab24 was significantly correlated with poorer prognosis of HCC patients,indicating the potential of Rab24 as a novel clinical biomarker and therapeutic target.
