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Organelle fusion

About: Organelle fusion is a research topic. Over the lifetime, 57 publications have been published within this topic receiving 3810 citations.


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Journal ArticleDOI
TL;DR: The recent progress in understanding the mechanisms governing mitochondrial morphology and the latest advances connecting the regulation of mitochondrial morphology with programmed cell death are discussed.
Abstract: Mitochondria exist as dynamic networks that often change shape and subcellular distribution. The number and morphology of mitochondria within a cell are controlled by precisely regulated rates of organelle fusion and fission. Recent reports have described dramatic alterations in mitochondrial morphology during the early stages of apoptotic cell death, a fragmentation of the network and the remodeling of the cristae. Surprisingly, proteins discovered to control mitochondrial morphology appear to also participate in apoptosis and proteins associated with the regulation of apoptosis have been shown to affect mitochondrial ultrastructure. In this review the recent progress in understanding the mechanisms governing mitochondrial morphology and the latest advances connecting the regulation of mitochondrial morphology with programmed cell death are discussed.

709 citations

Journal ArticleDOI
TL;DR: How bioenergetics and cellular signalling are linked to dynamic changes of mitochondrial morphology is described, with morphological changes to mitochondria accompanying a multitude of processes as diverse as cell pluripotency, division, differentiation, senescence and death.
Abstract: Owing to their ability to efficiently generate ATP required to sustain normal cell function, mitochondria are often considered the ‘powerhouses of the cell’. However, our understanding of the role of mitochondria in cell biology recently expanded when we recognized that they are key platforms for a plethora of cell signalling cascades. This functional versatility is tightly coupled to constant reshaping of the cellular mitochondrial network in a series of processes, collectively referred to as mitochondrial membrane dynamics and involving organelle fusion and fission (division) as well as ultrastructural remodelling of the membrane. Accordingly, mitochondrial dynamics influence and often orchestrate not only metabolism but also complex cell signalling events, such as those involved in regulating cell pluripotency, division, differentiation, senescence and death. Reciprocally, mitochondrial membrane dynamics are extensively regulated by post-translational modifications of its machinery and by the formation of membrane contact sites between mitochondria and other organelles, both of which have the capacity to integrate inputs from various pathways. Here, we discuss mitochondrial membrane dynamics and their regulation and describe how bioenergetics and cellular signalling are linked to these dynamic changes of mitochondrial morphology. Mitochondrial networks are dynamically remodelled via fusion, fission and ultrastructural changes to mitochondrial membranes. These mitochondrial membrane dynamics are tightly coupled to cell function, with morphological changes to mitochondria accompanying a multitude of processes as diverse as cell pluripotency, division, differentiation, senescence and death. Accordingly, disturbed dynamics of mitochondrial membranes are linked to severe human disorders.

562 citations

Journal ArticleDOI
TL;DR: A novel assay of mitochondrial dynamics based on confocal imaging of cells expressing a mitochondrial matrix–targeted photoactivable green fluorescent protein that enables detection and quantification of organelle fusion in living cells is described.
Abstract: A dynamic balance of organelle fusion and fission regulates mitochondrial morphology. During apoptosis this balance is altered, leading to an extensive fragmentation of the mitochondria. Here, we describe a novel assay of mitochondrial dynamics based on confocal imaging of cells expressing a mitochondrial matrix–targeted photoactivable green fluorescent protein that enables detection and quantification of organelle fusion in living cells. Using this assay, we visualize and quantitate mitochondrial fusion rates in healthy and apoptotic cells. During apoptosis, mitochondrial fusion is blocked independently of caspase activation. The block in mitochondrial fusion occurs within the same time range as Bax coalescence on the mitochondria and outer mitochondrial membrane permeabilization, and it may be a consequence of Bax/Bak activation during apoptosis.

426 citations

Journal ArticleDOI
TL;DR: The view is emerging that lysosomes are organelles for the storage of hydrolases, perhaps in an inactivated form, and such systems would permit simultaneous regulation of a number of unrelatedhydrolases.
Abstract: The endolysosomal system comprises a unique environment for proteolysis, which is regulated in a manner that apparently does not involve protease inhibitors. The system comprises a series of membrane-bound intracellular compartments, within which endocytosed material and redundant cellular components are hydrolysed. Endocytosed material tends to flow vectorially through the system, proceeding through the early endosome, the endosome carrier vesicle, the late endosome and the lysosome. Phagocytosis and autophagy provide alternative entry points into the system. Late endosomes, lysosome/late endosome hybrid organelles, phagosomes and autophagosomes are the principal sites for proteolysis. In each case, hydrolytic competence is due to components of the endolysosomal system, i.e. proteases, lysosome-associated membrane proteins, H(+)-ATPases and possibly cysteine transporters. The view is emerging that lysosomes are organelles for the storage of hydrolases, perhaps in an inactivated form. Once a substrate has entered a proteolytically competent environment, the rate-limiting proteolytic steps are probably effected by cysteine endoproteinases. As these are affected by pH and possibly redox potential, they may be regulated by the organelle luminal environment. Regulation is probably also affected, among other factors, by organelle fusion reactions, whereby the meeting of enzyme and substrate may be controlled. Such systems would permit simultaneous regulation of a number of unrelated hydrolases.

301 citations

Journal ArticleDOI
TL;DR: This work focuses on the cellular machinery that orchestrates assembly and disassembly of SNARE complexes, thereby regulating processes ranging from vesicle trafficking to organelle fusion to neurotransmitter release.
Abstract: Intracellular membrane fusion is mediated in most cases by membrane-bridging complexes of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). However, the assembly of such complexes in vitro is inefficient, and their uncatalysed disassembly is undetectably slow. Here, we focus on the cellular machinery that orchestrates assembly and disassembly of SNARE complexes, thereby regulating processes ranging from vesicle trafficking to organelle fusion to neurotransmitter release. Rapid progress is being made on many fronts, including the development of more realistic cell-free reconstitutions, the application of single-molecule biophysics, and the elucidation of X-ray and high-resolution electron microscopy structures of the SNARE assembly and disassembly machineries 'in action'.

198 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20212
20201
20194
20186
20174
20162