hydrolase activity
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2021 ◽  
Vol 118 (44) ◽  
pp. e2106022118
Author(s):  
Bartłomiej Salamaga ◽  
Lingyuan Kong ◽  
Laia Pasquina-Lemonche ◽  
Lucia Lafage ◽  
Milena von und zur Muhlen ◽  
...  

Bacterial cell wall peptidoglycan is essential, maintaining both cellular integrity and morphology, in the face of internal turgor pressure. Peptidoglycan synthesis is important, as it is targeted by cell wall antibiotics, including methicillin and vancomycin. Here, we have used the major human pathogen Staphylococcus aureus to elucidate both the cell wall dynamic processes essential for growth (life) and the bactericidal effects of cell wall antibiotics (death) based on the principle of coordinated peptidoglycan synthesis and hydrolysis. The death of S. aureus due to depletion of the essential, two-component and positive regulatory system for peptidoglycan hydrolase activity (WalKR) is prevented by addition of otherwise bactericidal cell wall antibiotics, resulting in stasis. In contrast, cell wall antibiotics kill via the activity of peptidoglycan hydrolases in the absence of concomitant synthesis. Both methicillin and vancomycin treatment lead to the appearance of perforating holes throughout the cell wall due to peptidoglycan hydrolases. Methicillin alone also results in plasmolysis and misshapen septa with the involvement of the major peptidoglycan hydrolase Atl, a process that is inhibited by vancomycin. The bactericidal effect of vancomycin involves the peptidoglycan hydrolase SagB. In the presence of cell wall antibiotics, the inhibition of peptidoglycan hydrolase activity using the inhibitor complestatin results in reduced killing, while, conversely, the deregulation of hydrolase activity via loss of wall teichoic acids increases the death rate. For S. aureus, the independent regulation of cell wall synthesis and hydrolysis can lead to cell growth, death, or stasis, with implications for the development of new control regimes for this important pathogen.


Author(s):  
Iris Munhoz Costa ◽  
Débora Custódio Moura ◽  
Guilherme Meira Lima ◽  
Adalberto Pessoa ◽  
Camila Oresco dos Santos ◽  
...  

2021 ◽  
pp. 100115
Author(s):  
Sujith Rajan ◽  
Hazel C. de Guzman ◽  
Thomas Palaia ◽  
Ira J. Goldberg ◽  
M. Mahmood Hussain

Author(s):  
Jing-jing Xu ◽  
Yong-mei Chang ◽  
Mei Lu ◽  
Yuan Tie ◽  
Yan-ling Dong ◽  
...  

Author(s):  
Meagan D. McLaren ◽  
Sabateeshan Mathavarajah ◽  
William D. Kim ◽  
Shyong Q. Yap ◽  
Robert J. Huber

Mutations in CLN5 cause a subtype of neuronal ceroid lipofuscinosis (NCL) called CLN5 disease. While the precise role of CLN5 in NCL pathogenesis is not known, recent work revealed that the protein has glycoside hydrolase activity. Previous work on the Dictyostelium discoideum homolog of human CLN5, Cln5, revealed its secretion during the early stages of development and its role in regulating cell adhesion and cAMP-mediated chemotaxis. Here, we used Dictyostelium to examine the effect of cln5-deficiency on various growth and developmental processes during the life cycle. During growth, cln5– cells displayed reduced cell proliferation, cytokinesis, viability, and folic acid-mediated chemotaxis. In addition, the growth of cln5– cells was severely impaired in nutrient-limiting media. Based on these findings, we assessed autophagic flux in growth-phase cells and observed that loss of cln5 increased the number of autophagosomes suggesting that the basal level of autophagy was increased in cln5– cells. Similarly, loss of cln5 increased the amounts of ubiquitin-positive proteins. During the early stages of multicellular development, the aggregation of cln5– cells was delayed and loss of the autophagy genes, atg1 and atg9, reduced the extracellular amount of Cln5. We also observed an increased amount of intracellular Cln5 in cells lacking the Dictyostelium homolog of the human glycoside hydrolase, hexosaminidase A (HEXA), further supporting the glycoside hydrolase activity of Cln5. This observation was also supported by our finding that CLN5 and HEXA expression are highly correlated in human tissues. Following mound formation, cln5– development was precocious and loss of cln5 affected spore morphology, germination, and viability. When cln5– cells were developed in the presence of the autophagy inhibitor ammonium chloride, the formation of multicellular structures was impaired, and the size of cln5– slugs was reduced relative to WT slugs. These results, coupled with the aberrant autophagic flux observed in cln5– cells during growth, support a role for Cln5 in autophagy during the Dictyostelium life cycle. In total, this study highlights the multifaceted role of Cln5 in Dictyostelium and provides insight into the pathological mechanisms that may underlie CLN5 disease.


2021 ◽  
Author(s):  
Selom K Doamekpor ◽  
Agnieszka Gozdek ◽  
Aleksandra Kwasnik ◽  
Joanna Kufel ◽  
Liang Tong
Keyword(s):  

Author(s):  
Vincenzo Alterio ◽  
Emma Langella ◽  
Martina Buonanno ◽  
Davide Esposito ◽  
Alessio Nocentini ◽  
...  

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