scholarly journals Pannexin-1 Channels govern the Generation of Necroptotic small Extracellular Vesicles

2019 ◽  
Author(s):  
Tiphaine Douanne ◽  
Gwennan André-Grégoire ◽  
Magalie Feyeux ◽  
Philippe Hulin ◽  
Julie Gavard ◽  
...  

ABSTRACTThe activation of mixed lineage kinase-like (MLKL) by receptor-interacting protein kinase-3 (RIPK3) controls the execution of necroptosis, a regulated form of necrosis that occurs in apoptosis-deficient conditions. Active oligomerized MLKL triggers the exposure of phosphatidylserine residues on the cell surface and disrupts the plasma membrane integrity by forming lytic pores. MLKL also governs the biogenesis and shedding of proinflammatory small extracellular vesicles (EVs) during the early steps of necroptosis, however the molecular basis is unknown. Here, we find that MLKL oligomers activate plasma membrane Pannexin-1 (PANX1) channels, concomitantly to the loss of phosphatidylserine asymmetry. This plasma membrane “leakiness” requires the Rab GTPase Rab27 isoforms, which usher the small EVs to their release. Conversely, PANX1 knockdown disorganized the small EVs machinery and precludes vesicles extrusion. These data identify a novel signaling nexus between MLKL, Rab27, and PANX1, and propose ways to interfere with small EV generation.

2019 ◽  
Vol 11 (21) ◽  
pp. 2831-2844
Author(s):  
Cristina D Guibao ◽  
Katherine Petrinjak ◽  
Tudor Moldoveanu

MLKL and its obligate upstream receptor interacting protein kinase 3 are essential components of necroptosis. It is well established that MLKL is the executioner of plasma membrane rupture in necroptosis. In healthy cells MLKL is dormant. Several dormant configurations have emerged from high-resolution structural studies revealing distinct mechanisms of MLKL autoinhibition in mammals. MLKL is activated through the concerted actions of receptor interacting protein kinase 3, which phosphorylates MLKL, and, in the case of the human pathway, inositol phosphate (IP) metabolites synthesized by the IP kinases of the IP metabolic pathway. Here, we highlight recent progress toward understanding the mechanisms of regulation of human MLKL, and survey the latest opportunities for targeting MLKL in pathophysiology.


2014 ◽  
Author(s):  
Mello Papa Patricia de ◽  
Carlos Ramires Neto ◽  
Priscilla Nascimento Guasti ◽  
Rosiara Rosaria Dias Maziero ◽  
Yame F R Sancler-Silva ◽  
...  

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Catarina Dias ◽  
Jesper Nylandsted

AbstractMaintenance of plasma membrane integrity is essential for normal cell viability and function. Thus, robust membrane repair mechanisms have evolved to counteract the eminent threat of a torn plasma membrane. Different repair mechanisms and the bio-physical parameters required for efficient repair are now emerging from different research groups. However, less is known about when these mechanisms come into play. This review focuses on the existence of membrane disruptions and repair mechanisms in both physiological and pathological conditions, and across multiple cell types, albeit to different degrees. Fundamentally, irrespective of the source of membrane disruption, aberrant calcium influx is the common stimulus that activates the membrane repair response. Inadequate repair responses can tip the balance between physiology and pathology, highlighting the significance of plasma membrane integrity. For example, an over-activated repair response can promote cancer invasion, while the inability to efficiently repair membrane can drive neurodegeneration and muscular dystrophies. The interdisciplinary view explored here emphasises the widespread potential of targeting plasma membrane repair mechanisms for therapeutic purposes.


BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Dustin A. Ammendolia ◽  
William M. Bement ◽  
John H. Brumell

AbstractPlasma membrane integrity is essential for cellular homeostasis. In vivo, cells experience plasma membrane damage from a multitude of stressors in the extra- and intra-cellular environment. To avoid lethal consequences, cells are equipped with repair pathways to restore membrane integrity. Here, we assess plasma membrane damage and repair from a whole-body perspective. We highlight the role of tissue-specific stressors in health and disease and examine membrane repair pathways across diverse cell types. Furthermore, we outline the impact of genetic and environmental factors on plasma membrane integrity and how these contribute to disease pathogenesis in different tissues.


1993 ◽  
Vol 21 (3) ◽  
pp. 324-329
Author(s):  
Jeffrey R. Fry ◽  
Alison H. Hammond

A variety of approaches to assessment of cellular integrity exist, based on tests of integrity of the plasma membrane, tests of metabolic competence, and asessment of morphology. By definition, such approaches address different aspects of cellular integrity and hence are not interchangeable indices of cellular integrity. Accordingly, it would be most appropriate to characterise hepatocyte preparations on the basis of more than just trypan blue dye exclusion (a test of plasma membrane integrity) as is customary. A scheme for the choice of the most appropriate mix of tests of cellular integrity is presented.


1999 ◽  
Vol 144 (3) ◽  
pp. 403-411 ◽  
Author(s):  
Shun'ichi Kuroda ◽  
Noritaka Nakagawa ◽  
Chiharu Tokunaga ◽  
Kenji Tatematsu ◽  
Katsuyuki Tanizawa

By the yeast two-hybrid screening of a rat brain cDNA library with the regulatory domain of protein kinase C ζ (PKCζ) as a bait, we have cloned a gene coding for a novel PKCζ-interacting protein homologous to the Caenorhabditis elegans UNC-76 protein involved in axonal outgrowth and fasciculation. The protein designated FEZ1 (fasciculation and elongation protein zeta-1) consisting of 393 amino acid residues shows a high Asp/Glu content and contains several regions predicted to form amphipathic helices. Northern blot analysis has revealed that FEZ1 mRNA is abundantly expressed in adult rat brain and throughout the developmental stages of mouse embryo. By the yeast two-hybrid assay with various deletion mutants of PKC, FEZ1 was shown to interact with the NH2-terminal variable region (V1) of PKCζ and weakly with that of PKCε. In the COS-7 cells coexpressing FEZ1 and PKCζ, FEZ1 was present mainly in the plasma membrane, associating with PKCζ and being phosphorylated. These results indicate that FEZ1 is a novel substrate of PKCζ. When the constitutively active mutant of PKCζ was used, FEZ1 was found in the cytoplasm of COS-7 cells. Upon treatment of the cells with a PKC inhibitor, staurosporin, FEZ1 was translocated from the cytoplasm to the plasma membrane, suggesting that the cytoplasmic translocation of FEZ1 is directly regulated by the PKCζ activity. Although expression of FEZ1 alone had no effect on PC12 cells, coexpression of FEZ1 and constitutively active PKCζ stimulated the neuronal differentiation of PC12 cells. Combined with the recent finding that a human FEZ1 protein is able to complement the function of UNC-76 necessary for normal axonal bundling and elongation within axon bundles in the nematode, these results suggest that FEZ1 plays a crucial role in the axon guidance machinery in mammals by interacting with PKCζ.


1984 ◽  
Vol 247 (5) ◽  
pp. C382-C389 ◽  
Author(s):  
W. J. Armitage ◽  
P. Mazur

Human granulocytes are damaged by exposure to concentrations of glycerol as low as 0.5 M. We therefore investigated the addition of glycerol to granulocytes and its subsequent dilution under various conditions to try to distinguish between toxic and harmful osmotic effects of glycerol. The lesion caused by glycerol at 0 degree C was expressed as a loss of plasma membrane integrity (as visualized by fluorescein diacetate) only after incubation (greater than or equal to 1 h) at 37 degrees C. This damage was not ameliorated when osmotic stress was lessened by reducing the rates of addition and dilution of glycerol to keep the computed cell volume within 80-170% of isotonic cell volume. However, when osmotic stress was reduced further by increasing the temperature of addition and dilution of glycerol from 0 degree C to 22 degrees C, the tolerance of the cells to 1 M glycerol increased somewhat. Reducing exposure to glycerol to 3 min or less at 0 degree C greatly increased survival, but this time was too short to allow glycerol to equilibrate intracellularly. Finally, the presence of extra impermeant solute (NaCl or sucrose) in the medium to reduce the equilibrium cell volume to 60% of isotonic cell volume enabled granulocytes to survive 30-min exposure to 1 M glycerol at 0 degree C, but cells had to remain shrunken during the 37 degrees C incubation to prevent the loss of membrane integrity. Suspensions that contained damaged granulocytes formed aggregates when incubated at 37 degrees C, and these aggregates were responsible for a major fraction of the observed loss in viability.


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