scholarly journals NDST3 deacetylates α‐tubulin and suppresses V‐ATPase assembly and lysosomal acidification

2021 ◽  
Author(s):  
Qing Tang ◽  
Mingming Liu ◽  
Yang Liu ◽  
Ran‐Der Hwang ◽  
Tao Zhang ◽  
...  
Keyword(s):  
Lysosomal Acidification

scholarly journals Presenilins: A novel link between intracellular calcium signaling and lysosomal function?

2012 ◽  
Vol 198 (1) ◽  
pp. 7-10 ◽  
Author(s):  
Ilya Bezprozvanny
Keyword(s):  
Calcium Signaling ◽  
Intracellular Calcium ◽  
Transmembrane Proteins ◽  
Catalytic Subunit ◽  
Familial Alzheimer’S Disease ◽  
Lysosomal Function ◽  
Cell Biol ◽  
Intracellular Calcium Signaling ◽  
Lysosomal Acidification ◽  
In Cells

Mutations in presenilins (PS), transmembrane proteins encoding the catalytic subunit of γ-secretase, result in familial Alzheimer’s disease (FAD). Several studies have identified lysosomal defects in cells lacking PS or expressing FAD-associated PS mutations, which have been previously attributed to a function for PS in lysosomal acidification. Now, in this issue, Coen et al. (2012. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201201076) provide a series of results that challenge this idea and propose instead that presenilins play a role in calcium-mediated lysosomal fusion.

scholarly journals Retraction Notice to: VMA21 Deficiency Causes an Autophagic Myopathy by Compromising V-ATPase Activity and Lysosomal Acidification

Cell ◽  
2010 ◽  
Vol 142 (6) ◽  
pp. 984 ◽  
Author(s):  
Nivetha Ramachandran ◽  
Iulia Munteanu ◽  
Peixiang Wang ◽  
Pauline Aubourg ◽  
Jennifer J. Rilstone ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Retraction Notice ◽  
Lysosomal Acidification

scholarly journals Loss of TBK1 activity leads to TDP-43 proteinopathy through lysosomal dysfunction in human motor neurons

2021 ◽  
Author(s):  
Jin Hao ◽  
Michael F Wells ◽  
Gengle Niu ◽  
Irune Guerra San Juan ◽  
Francesco Limone ◽  
...  
Keyword(s):  
Motor Neuron ◽  
Neurodegenerative Disease ◽  
Motor Neurons ◽  
Inhibition Mechanism ◽  
Loss Of Function ◽  
Neurodegenerative Process ◽  
Lysosomal Dysfunction ◽  
Human Motor ◽  
Lateral Sclerosis ◽  
Lysosomal Acidification

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron loss accompanied by cytoplasmic localization of TDP-43 proteins and their insoluble accumulations. Haploinsufficiency of TBK1 has been found to associate with or cause ALS. However, the cell-autonomous mechanisms by which reduced TBK1 activity contributes to human motor neuron pathology remain elusive. Here, we generated a human cellular model harboring loss-of-function mutations of TBK1 by gene editing and found that TBK1 deficiency was sufficient to cause TDP-43 pathology in human motor neurons. In addition to its functions in autophagy, we found that TBK1 interacted with endosomes and was required for normal endosomal maturation and subsequent lysosomal acidification. Surprisingly, TDP-43 pathology resulted more from the dysfunctional endo-lysosomal pathway than the previously recognized autophagy inhibition mechanism. Restoring TBK1 levels ameliorated lysosomal dysfunction and TDP-43 pathology and maintained normal motor neuron homeostasis. Notably, using patient-derived motor neurons, we found that haploinsufficiency of TBK1 sensitized neurons to lysosomal stress, and chemical regulators of endosomal maturation rescued the neurodegenerative process. Together, our results revealed the mechanism of TBK1 in maintaining TDP-43 and motor neuron homeostasis and suggested that modulating endosomal maturation was able to rescue neurodegenerative disease phenotypes caused by TBK1 deficiency.

scholarly journals PAT2 regulates autophagy through vATPase assembly and lysosomal acidification in brown adipocytes

2020 ◽  
Author(s):  
Jiefu Wang ◽  
Martin Krueger ◽  
Stefanie M. Hauck ◽  
Siegfried Ussar
Keyword(s):  
Amino Acid ◽  
Brown Adipocyte ◽  
Amino Acid Transporters ◽  
Mitochondrial Uncoupling ◽  
Brown Adipocytes ◽  
Brown Adipose ◽  
Glucose And Lipid Homeostasis ◽  
Mtorc1 Activation ◽  
Lysosomal Acidification

Brown adipose tissue (BAT) plays a key role in maintaining body temperature as well as glucose and lipid homeostasis by its ability to dissipate energy through mitochondrial uncoupling. To facilitate these tasks BAT needs to adopt its thermogenic activity and substrate utilization to changes in nutrient availability, regulated by a complex network of neuronal, endocrine and nutritional inputs. Amongst this multitude of factors influencing BAT activity changes in the autophagic response of brown adipocytes are an important regulator of its thermogenic capacity and activity. Increasing evidence supports an important role of amino acid transporters in mTORC1 activation and the regulation of autophagy. However, a specific role of amino acid transporters in BAT regulating its function has not been described. Here we show that the brown adipocyte specific proton coupled amino acid transporter PAT2 rapidly translocates from the plasma membrane to the lysosome in response to amino acid withdrawal, where it facilitates the assembly of the lysosomal vATPase. Loss or overexpression of PAT2 therefore impair lysosomal acidification, autophagolysosome formation and starvation induced mTORC1 activation.

ML-SA1, a selective TRPML agonist, inhibits DENV2 and ZIKV by promoting lysosomal acidification and protease activity

2020 ◽  
Vol 182 ◽  
pp. 104922
Author(s):  
Zhiqiang Xia ◽  
Luyao Wang ◽  
Songryong Li ◽  
Wei Tang ◽  
Fang Sun ◽  
...  
Keyword(s):  
Protease Activity ◽  
Lysosomal Acidification

scholarly journals MAP1B Interaction with the FW Domain of the Autophagic Receptor Nbr1 Facilitates Its Association to the Microtubule Network

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Katie Marchbank ◽  
Sarah Waters ◽  
Roland G. Roberts ◽  
Ellen Solomon ◽  
Caroline A. Whitehouse
Keyword(s):  
Protein Degradation ◽  
Microtubule Network ◽  
Protein Levels ◽  
Ubiquitinated Proteins ◽  
Autophagy Induction ◽  
Evolutionarily Conserved ◽  
Cargo Proteins ◽  
Autophagic Degradation ◽  
Membrane Bound ◽  
Lysosomal Acidification

Selective autophagy is a process whereby specific targeted cargo proteins, aggregates, or organelles are sequestered into double-membrane-bound phagophores before fusion with the lysosome for protein degradation. It has been demonstrated that the microtubule network is important for the formation and movement of autophagosomes. Nbr1 is a selective cargo receptor that through its interaction with LC3 recruits ubiquitinated proteins for autophagic degradation. This study demonstrates an interaction between the evolutionarily conserved FW domain of Nbr1 with the microtubule-associated protein MAP1B. Upon autophagy induction, MAP1B localisation is focused into discrete vesicles with Nbr1. This colocalisation is dependent upon an intact microtubule network as depolymerisation by nocodazole treatment abolishes starvation-induced MAP1B recruitment to these vesicles. MAP1B is not recruited to autophagosomes for protein degradation as blockage of lysosomal acidification does not result in significant increased MAP1B protein levels. However, the protein levels of phosphorylated MAP1B are significantly increased upon blockage of autophagic degradation. This is the first evidence that links the ubiquitin receptor Nbr1, which shuttles ubiquitinated proteins to be degraded by autophagy, to the microtubule network.

scholarly journals Prodigiosins uncouple lysosomal vacuolar-type ATPase through promotion of H+/Cl− symport

1998 ◽  
Vol 334 (3) ◽  
pp. 731-741 ◽  
Author(s):  
Shoji OHKUMA ◽  
Tomohiko SATO ◽  
Masayuki OKAMOTO ◽  
Hidekazu MATSUYA ◽  
Kunizo ARAI ◽  
...  
Keyword(s):  
Atp Hydrolysis ◽  
Dependent Manner ◽  
Lysosomal Ph ◽  
Vacuolar Acidification ◽  
Ic50 Values ◽  
Atp Inhibition ◽  
Glycoprotein Processing ◽  
Type V ◽  
Micro Organisms ◽  
Lysosomal Acidification

We reported previously [Kataoka, Muroi, Ohkuma, Waritani, Magae, Takatsuki, Kondo, Yamasaki and Nagai (1995) FEBS Lett. 359, 53–59] that prodigiosin 25-C (one of the red pigments of the prodigiosin group produced by micro-organisms like Streptomycesand Serratia) uncoupled vacuolar H+-ATPase, inhibited vacuolar acidification and affected glycoprotein processing. In the present study we show that prodigiosin, metacycloprodigiosin and prodigiosin 25-C, all raise intralysosomal pH through inhibition of lysosomal acidification driven by vacuolar-type (V-)ATPase without inhibiting ATP hydrolysis in a dose-dependent manner with IC50 values of 30–120 pmol/mg of protein. The inhibition against lysosomal acidification was quick and reversible, showing kinetics of simple non-competitive (for ATP) inhibition. However, the prodigiosins neither raised the internal pH of isolated lysosomes nor showed ionophoric activity against H+ or K+ at concentrations where they strongly inhibited lysosomal acidification. They required Cl- for their acidification inhibitory activity even when driven in the presence of K+ and valinomycin, suggesting that their target is not anion (chloride) channel(s). In fact, the prodigiosins inhibited acidification of proteoliposomes devoid of anion channels that were reconstituted from lysosomal vacuolar-type (V-)ATPase and Escherichia coli phospholipids. However, they did not inhibit the formation of an inside-positive membrane potential driven by lysosomal V-ATPase. Instead, they caused quick reversal of acidified pH driven by lysosomal V-ATPase and, in acidic buffer, produced quick acidification of lysosomal pH, both only in the presence of Cl-. In addition, they induced swelling of liposomes and erythrocytes in iso-osmotic ammonium salt of chloride but not of gluconate, suggesting the promotion of Cl- entry by prodigiosins. These results suggest that prodigiosins facilitate the symport of H+ with Cl- (or exchange of OH- with Cl-) through lysosomal membranes, resulting in uncoupling of vacuolar H+-ATPase.

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