Role of the BH3 (Bcl-2 homology 3) domain in the regulation of apoptosis and Bcl-2-related proteins

2000 ◽  
Vol 28 (2) ◽  
pp. 51-56 ◽  
Author(s):  
R. J. Lutz

The Bcl-2 family of proteins play a prominent role in the regulation of apoptosis. From the initial identification of bcl-2 as an oncogene in follicular lymphoma through genetic studies in Caenorhabditis elegans to recent functional studies focusing on the importance of mitochondrial events in cell death signalling, the members of this protein family continue to be implicated in pivotal decision points regarding the survival of the cell. The family can be divided into two classes: those such as Bcl-2 and Bcl-xL that suppress cell death, and others, such as Bak and Bax, that appear to promote apoptosis. The Bcl-2 family is characterized by specific regions of homology termed Bcl-2 homology (BH1, BH2, BH3, BH4) domains, which are critical to the function of these proteins, including their impact on cell survival and their ability to interact with other family members and regulatory proteins. The identification of the BH3 domain as a potent mediator of cell death has led to the emergence of an additional family of pro-apoptotic proteins (such as Bad, Bik, Bid and Hrk) that share identity with Bcl-2 only within this death domain. These BH3-only proteins may be part of a regulatory network serving to integrate cell survival and death signals, an assertion that is supported by the identification of a BH3-only protein, Egl-1, as part of the central core of cell death signalling in C. elegans. While the mechanism of action of the BH3-only proteins remains unclear, recent studies on the regulation of critical protein-protein interactions and activity of Bad by phosphorylation in response to growth factor signalling suggest that the active state of BH3-only proteins may be regulated by post-translational modification. Additional modes of regulation, such as transcriptional, translational and subcellular localization, are also likely to be important.

2005 ◽  
Vol 388 (1) ◽  
pp. 185-194 ◽  
Author(s):  
Mário GRÃOS ◽  
Alexandra D. ALMEIDA ◽  
Sukalyan CHATTERJEE

The regulation of survival and cell death is a key determinant of cell fate. Recent evidence shows that survival and death machineries are regulated along the cell cycle. In the present paper, we show that BimEL [a BH3 (Bcl-2 homology 3)-only member of the Bcl-2 family of proteins; Bim is Bcl-2-interacting mediator of cell death; EL is the extra-long form] is phosphorylated in mitosis. This post-translational modification is dependent on MEK (mitogen-activated protein kinase/extracellular-signal-regulated kinase kinase) and growth factor signalling. Interestingly, FGF (fibroblast growth factor) signalling seems to play an essential role in this process, since, in the presence of serum, inhibition of FGF receptors abrogated phosphorylation of Bim in mitosis. Moreover, we have shown bFGF (basic FGF) to be sufficient to induce phosphorylation of Bim in serum-free conditions in any phase of the cell cycle, and also to significantly rescue cells from serum-deprivation-induced apoptosis. Our results show that, in mitosis, Bim is phosphorylated downstream of growth factor signalling in a MEK-dependent manner, with FGF signalling playing an important role. We suggest that phosphorylation of Bim is a decisive step for the survival of proliferating cells.


2003 ◽  
Vol 23 (21) ◽  
pp. 7838-7848 ◽  
Author(s):  
Nerina Gnesutta ◽  
Audrey Minden

ABSTRACT Normal cell growth requires a precisely controlled balance between cell death and survival. This involves activation of different types of intracellular signaling cascades within the cell. While some types of signaling proteins regulate apoptosis, or programmed cell death, other proteins within the cell can promote survival. The serine/threonine kinase PAK4 can protect cells from apoptosis in response to several different types of stimuli. As is the case for other members of the p21-activated kinase (PAK) family, one way that PAK4 may promote cell survival is by phosphorylating and thereby inhibiting the proapoptotic protein Bad. This leads in turn to the inhibition of effector caspases such as caspase 3. Here we show that in response to cytokines which activate death domain-containing receptors, such as the tumor necrosis factor and Fas receptors, PAK4 can inhibit the death signal by a different mechanism. Under these conditions, PAK4 inhibits apoptosis early in the caspase cascade, antagonizing the activation of initiator caspase 8. This inhibition, which does not require PAK4's kinase activity, may involve inhibition of caspase 8 recruitment to the death domain receptors. This role in regulating initiator caspases is an entirely novel role for the PAK proteins and suggests a new mechanism by which these proteins promote cell survival.


2021 ◽  
Vol 12 ◽  
Author(s):  
Manlin Xu ◽  
Xia Zhang ◽  
Jing Yu ◽  
Zhiqing Guo ◽  
Ying Li ◽  
...  

Aspergillus niger is a very destructive pathogen causing severe peanut root rot, especially in the seeding stage of peanuts (Arachis hypogaea), and often leading to the death of the plant. Protein lysine 2-hydroxyisobutyrylation (Khib) is a newly detected post-translational modification identified in several species. In this study, we identified 5041 Khib sites on 1,453 modified proteins in A. niger. Compared with five other species, A. niger has conserved and novel proteins. Bioinformatics analysis showed that Khib proteins are widely distributed in A. niger and are involved in many biological processes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that Khib proteins were significantly enriched in many cellular compartments and pathways, such as ribosomes and proteasome subunits. A total of 223 Khib proteins were part of the PPI network, thus, suggesting that Khib proteins are associated with a large range of protein interactions and diverse pathways in the life processes of A. niger. Several identified proteins are involved in pathogenesis regulation. Our research provides the first comprehensive report of Khib and an extensive database for potential functional studies on Khib proteins in this economically important fungus.


2015 ◽  
Vol 43 (2) ◽  
pp. 229-234 ◽  
Author(s):  
Dale D.O. Martin ◽  
Michael R. Hayden

In a little more than a decade, post-translational myristoylation (PTMyr) has become an established post-translational modification during cell death. It involves the addition of the fatty acid myristate to newly exposed N-terminal glycines following caspase cleavage. It promotes membrane binding and relocalization of functional protein domains released by caspase cleavage during apoptosis, or programmed cell death. However, as the requirement of caspase cleavage has expanded beyond just cell death, it has become apparent that PTMyr may play a role in cell survival, differentiation and now autophagy. Herein, we describe how myristoylation may play a role in autophagy with an emphasis on PTMyr.


2019 ◽  
Author(s):  
Nadiia Rawlings ◽  
Laura Lee ◽  
Yasuko Nakamura ◽  
Kevin A. Wilkinson ◽  
Jeremy M Henley

AbstractInterruption of blood supply to the heart is a leading cause of death and disability. However, the molecular events that occur during heart ischaemia, and how these changes prime consequent cell death upon reperfusion, are poorly understood. Protein SUMOylation is a post-translational modification that has been strongly implicated in the protection of cells against a variety of stressors, including ischaemia-reperfusion. In particular, the SUMO2/3-specific protease SENP3 has emerged as an important determinant of cell survival after ischaemic infarct. Here, we used the Langendorff perfusion model to examine changes in the levels and localisation of SUMOylated target proteins and SENP3 in whole heart. We observed a 50% loss of SENP3 from the cytosolic fraction of hearts after preconditioning, a 90% loss after ischaemia and an 80% loss after ischaemia-reperfusion. To examine these effects further, we performed ischaemia and ischaemia-reperfusion experiments in the cardiomyocyte H9C2 cell line. Similar to whole hearts, ischaemia induced a decrease in cytosolic SENP3. Furthermore, shRNA-mediated knockdown of SENP3 led to an increase in the rate of cell death upon reperfusion. Together, our results indicate that cardiac ischaemia dramatically alter levels of SENP3 and suggest that this may a mechanism to promote cell survival after ischaemia-reperfusion in heart.


Author(s):  
Maria T. Nuzzo ◽  
Marco Fiocchetti ◽  
Paolo Ascenzi ◽  
Maria Marino

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 587-595 ◽  
Author(s):  
Mario de Bono ◽  
Jonathan Hodgkin

Abstract The tra-1 gene is a terminal regulator of somatic sex in Caenorhabditis elegans: high tra-1 activity elicits female development, low tra-1 activity elicits male development. To investigate the function and evolution of tra-1, we examined the tra-1 gene from the closely related nematode C. briggsae. Ce-tra-1 and Cb-tra-1 are unusually divergent. Each gene generates two transcripts, but only one of these is present in both species. This common transcript encodes TRA-1A, which shows only 44% amino acid identity between the species, a figure much lower than that for previously compared genes. A Cb-tra-1 transgene rescues many tissues of tra-1(nul1) mutants of C. elegans but not the somatic gonad or germ line. This transgene also causes nongonadal feminization of XO animals, indicating incorrect sexual regulation. Alignment of Ce-TRA-1A and Cb-TRA-1A defines several conserved regions likely to be important for tra-1 function. The phenotypic differences between Ce-tra-1(null) mutants rescued by Cb-tra-1 transgenes and wild-type C. elegans indicate significant divergence of regulatory regions. These molecular and functional studies suggest that evolution of sex determination in nematodes is rapid and genetically complex.


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