scholarly journals Desmosomal dualism: the core is stable while plakophilin is dynamic

2021 ◽  
Author(s):  
Judith B Fülle ◽  
Henri Huppert ◽  
David Liebl ◽  
Jaron Liu ◽  
Rogerio Alves de Almeida ◽  
...  
Keyword(s):  
Live Cell Imaging ◽  
Cell Imaging ◽  
Core Stability ◽  
Cell Junctions ◽  
Major Protein ◽  
Desmosomal Cadherins ◽  
The Core ◽  
Cell Scattering ◽  
Stable Core ◽  
Protein Classes

Desmosomes, strong cell-cell junctions of epithelia and cardiac muscle, link intermediate filaments to cell membranes and mechanically integrate cells across tissues, dissipating mechanical stress. They comprise 5 major protein classes - desmocollins and desmogleins (the desmosomal cadherins), plakoglobin, plakophilins and desmoplakin - whose individual contribution to the structure and turnover of desmosomes is poorly understood. Using live-cell imaging together with FRAP and FLAP we show that desmosomes consist of two contrasting protein fractions or modules: a very stable desmosomal core of desmosomal cadherins and plakoglobin, and a highly mobile plakophilin. As desmosomes mature from calcium-dependence to calciumindependent hyper-adhesion, core stability increases, but Pkp2a remains highly mobile. Desmoplakin is initially mobile but stabilises with hyper-adhesion. We show that desmosome down-regulation during growth factor-induced cell scattering proceeds by internalisation of whole desmosomes, which still retain a stable core and highly mobile Pkp2a. This molecular mobility of Pkp2a suggests a transient and probably regulatory role for Pkp2a in the desmosome.

scholarly journals Desmosome dualism: most of the junction is stable but a plakophilin moiety is persistently dynamic

2021 ◽  
Author(s):  
Judith B. Fülle ◽  
Henri Huppert ◽  
David Liebl ◽  
Jaron Liu ◽  
Rogerio Alves de Almeida ◽  
...  
Keyword(s):  
Growth Factor ◽  
Intermediate Filaments ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Cell Junctions ◽  
Major Protein ◽  
Individual Contribution ◽  
Desmosomal Cadherins ◽  
Cell Scattering ◽  
Protein Classes

Desmosomes, strong cell-cell junctions of epithelia and cardiac muscle, link intermediate filaments to cell membranes and mechanically integrate cells across tissues, dissipating mechanical stress. They comprise five major protein classes – desmocollins and desmogleins (the desmosomal cadherins), plakoglobin, plakophilins and desmoplakin - whose individual contribution to the structure and turnover of desmosomes is poorly understood. Using live-cell imaging together with FRAP and FLAP we show that desmosomes consist of two contrasting protein moieties or modules: a very stable moiety of desmosomal cadherins, desmoplakin and plakoglobin, and a highly mobile plakophilin (Pkp2a). As desmosomes mature from calcium-dependence to calcium-independent hyper-adhesion, their stability increases, but Pkp2a remains highly mobile. We show that desmosome down-regulation during growth-factor-induced cell scattering proceeds by internalisation of whole desmosomes, which still retain a stable moiety and highly mobile Pkp2a. This molecular mobility of Pkp2a suggests a transient and probably regulatory role for Pkp2a in desmosomes.

scholarly journals Traffic watch: Live-cell imaging

2003 ◽  
Vol 25 (3) ◽  
pp. 15-17
Author(s):  
David J. Stephens
Keyword(s):  
Electron Microscopy ◽  
Cell Biology ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Living Cells ◽  
Robert Hooke ◽  
The Core ◽  
Biology Research ◽  
Insight Into ◽  
Dynamics Process

Microscopy has been at the core of cell biology research ever since the coining of the term ‘cell’ by Robert Hooke in the 17th Century1. For many years, it has been possible to gain insight into ‘steady-state’ cellular function from the analysis of fixed samples, but it is only relatively recently that imaging of living cells has become a widely used tool to support biochemical and electron microscopy studies. Membrane traffic research, which by its very nature is a highly dynamics process, has benefited hugely from the ability to image specific processes in living cells and tissues.

scholarly journals Direct observation of aggregate-triggered selective autophagy

2021 ◽  
Author(s):  
Anne FJ Janssen ◽  
Giel Korsten ◽  
Wilco Nijenhuis ◽  
Eugene Katrukha ◽  
Lukas Kapitein
Keyword(s):  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Relative Timing ◽  
Imaging Studies ◽  
Selective Autophagy ◽  
The Core ◽  
Spatiotemporal Regulation ◽  
Core Components ◽  
Inducible Protein

Degradation of aggregates by selective autophagy is important as damaged proteins may impose a threat to cellular homeostasis. Although the core components of the autophagy machinery are well-characterized, the spatiotemporal regulation of many selective autophagy processes, including aggrephagy, remains largely unexplored. Furthermore, because most live-cell imaging studies have so far focused on starvation-induced autophagy, little is known about the dynamics of aggrephagy. Here, we describe the development and application of the mKeima-PIM assay, which enables live-cell observation of autophagic turnover and degradation of inducible protein aggregates in conjunction with key autophagy players. This allowed us to quantify the relative timing and duration of different steps of aggrephagy and revealed the short-lived nature of the autophagosome. The assay furthermore showed the spatial distribution of omegasome formation, highlighting that autophagy initiation is directly instructed by the cargo. Moreover, we found that nascent autophagosomes mostly remain immobile until acidification occurs. Thus, our assay provides new insights into the spatiotemporal regulation and dynamics of aggrephagy.

Live Cell Imaging: Building the Perfect System for the Core Imaging Facility

2008 ◽  
Vol 14 (S2) ◽  
pp. 714-715
Author(s):  
SC Watkins
Keyword(s):  
New Mexico ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
The Core ◽  
Perfect System

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

scholarly journals Direct observation of aggregate-triggered selective autophagy

2021 ◽  
Author(s):  
Anne F.J. Janssen ◽  
Giel Korsten ◽  
Wilco Nijenhuis ◽  
Eugene A. Katrukha ◽  
Lukas C. Kapitein
Keyword(s):  
Live Cell Imaging ◽  
Cell Imaging ◽  
Live Cell ◽  
Relative Timing ◽  
Imaging Studies ◽  
Selective Autophagy ◽  
The Core ◽  
Spatiotemporal Regulation ◽  
Core Components ◽  
Inducible Protein

Degradation of aggregates by selective autophagy is important as damaged proteins may impose a threat to cellular homeostasis. Although the core components of the autophagy machinery are well-characterized, the spatiotemporal regulation of many selective autophagy processes, including aggrephagy, remains largely unexplored. Furthermore, because most live-cell imaging studies have so far focused on starvation-induced autophagy, little is known about the dynamics of aggrephagy. Here, we describe the development and application of the mKeima-PIM assay, which enables live-cell observation of autophagic turnover and degradation of inducible protein aggregates in conjunction with key autophagy players. This allowed us to quantify the relative timing and duration of different steps of aggrephagy and revealed the short-lived nature of the autophagosome. The assay furthermore showed the spatial distribution of omegasome formation, highlighting that autophagy initiation is directly instructed by the cargo. Moreover, we found that nascent autophagosomes mostly remain immobile until acidification occurs. Thus, our assay provides new insights into the spatiotemporal regulation and dynamics of aggrephagy.

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