Measurement of BH3-only protein tolerance

Dai, Haiming; Ding, Husheng; Peterson, Kevin; Meng, Xue; Schneider, Paula A.; Knorr, Katherine; Kaufmann, Scott H.

doi:10.1038/cdd.2017.156

Cited by 22 publications

(17 citation statements)

References 59 publications

(109 reference statements)

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“…This is in contrast to a previous report that observed the expression of an NDK-1:: GFP reporter solely in the distal tip cell (DTC) and somatic gonadal sheath cells [33]. Increasing evidence indicates that death signals must overcome a threshold for a cell to undergo apoptosis [45][46][47]. We observed a dramatic increase in perinuclear GFP::NDK-1 localization in germ cells, minutes before they exhibited the refractile morphology characteristic of apoptosis ( Fig.…”

Section: Ndk-1 Expression Increases Prior To Cell Deathcontrasting

confidence: 99%

MiR-35 buffers apoptosis thresholds in the C. elegans germline by antagonizing both MAPK and core apoptosis pathways

et al. 2019

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Apoptosis is a genetically programmed cell death process with profound roles in development and disease. MicroRNAs modulate the expression of many proteins and are often deregulated in human diseases, such as cancer. C. elegans germ cells undergo apoptosis in response to genotoxic stress by the combined activities of the core apoptosis and MAPK pathways, but how their signalling thresholds are buffered is an open question. Here we show mir-35-42 miRNA family play a dual role in antagonizing both NDK-1, a positive regulator of MAPK signalling, and the BH3-only pro-apoptotic protein EGL-1 to regulate the magnitude of DNA damage-induced apoptosis in the C. elegans germline. We show that while miR-35 represses EGL-1 by promoting transcript degradation, repression of NDK-1 may be through sequestration of the transcript to inhibit translation. Importantly, dramatic increase in NDK-1 expression was observed in cells about to die. In the absence of miR-35, increased NDK-1 activity enhanced MAPK signalling that lead to significant increases in germ cell death. Our findings demonstrate that NDK-1 acts upstream of (or in parallel to) EGL-1, and that miR-35 targets both egl-1 and ndk-1 to fine-tune cell killing in response to genotoxic stress.

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Section: Ndk-1 Expression Increases Prior To Cell Deathcontrasting

confidence: 99%

MiR-35 buffers apoptosis thresholds in the C. elegans germline by antagonizing both MAPK and core apoptosis pathways

et al. 2019

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“…Noxa upregulation and disrupted bindings of Mcl-1 to Bax and Bak contribute to both KPNB1 knockdown and IPZ-induced apoptosis, whereas Puma upregulation and disrupted bindings of Bcl-xL to Bax or Bak simply contribute to KPNB1 knockdown-induced apoptosis. One explanation is that the tolerances for different BH3-only proteins vary among different cell types [ 47 ]. U87 and U251 cells may tolerate higher levels of Puma than Noxa.…”

Section: Discussionmentioning

confidence: 99%

KPNB1 inhibition disrupts proteostasis and triggers unfolded protein response-mediated apoptosis in glioblastoma cells

Zhu

Liu

et al. 2018

Oncogene

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The nuclear import receptor karyopherin β1 (KPNB1) is involved in the nuclear import of most proteins and in the regulation of multiple mitotic events. Upregulation of KPNB1 has been observed in cancers including glioblastoma. Depletion of KPNB1 induces mitotic arrest and apoptosis in cancer cells, but the underlying mechanism is not clearly elucidated. Here, we found that downregulation and functional inhibition of KPNB1 in glioblastoma cells induced growth arrest and apoptosis without apparent mitotic arrest. KPNB1 inhibition upregulated Puma and Noxa and freed Mcl-1-sequestered Bax and Bak, leading to mitochondrial outer membrane permeabilization (MOMP) and apoptosis. Moreover, combination of Bcl-xL inhibitors and KPNB1 inhibition enhanced apoptosis in glioblastoma cells. KPNB1 inhibition promoted cytosolic retention of its cargo and impaired cellular proteostasis, resulting in elevated polyubiquitination, formation of aggresome-like-induced structure (ALIS), and unfolded protein response (UPR). Ubiquitination elevation and UPR activation in KPNB1-deficient cells were reversed by KPNB1 overexpression or inhibitors of protein synthesis but aggravated by inhibitors of autophagy-lysosome or proteasome, indicating that rebalance of cytosolic/nuclear protein distribution and alleviation of protein overload favor proteostasis and cell survival. Chronic activation of eIF2α/ATF4 cascade of UPR was responsible for the upregulation of Puma and Noxa, apoptosis and ABT-263 sensitivity. Taken together, our findings demonstrate that KPNB1 is required for proteostasis maintenance and its inhibition induces apoptosis in glioblastoma cells through UPR-mediated deregulation of Bcl-2 family members.

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“…As a quantitative readout, the amount of BH3‐only molecules that causes 98% cell death has been defined as the ‘BH3‐only tolerance’. This threshold value is around 120 000–280 000 BH3‐only protein copies per Jurkat cell for the BH3‐only proteins BimEL, Puma, Noxa, Bmf, Bik, and Hrk . Interestingly, while sensitizer and activator BH3‐only protein thresholds fell into this range, these cells displayed a BH3‐only tolerance to the BH3‐only protein Bad that was two orders of magnitudes higher.…”

Section: What Are the Cellular Concentrations And Proapoptotic Threshmentioning

confidence: 94%

“…Malignant lymphoid cell lines express different Bcl‐2 proteins in the order of 2000–200 000 molecules per cell . In colon carcinoma and triple negative breast cancer cells, the absolute concentrations ranged from low nanomolar to low micromolar protein concentrations .…”

Section: What Are the Cellular Concentrations And Proapoptotic Threshmentioning

confidence: 99%

Counting on Death – Quantitative aspects of Bcl‐2 family regulation

2018

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The Bcl-2 protein family members critically regulate mitochondrial outer membrane permeabilization (MOMP), a point-of-no-return in the intrinsic and extrinsic apoptosis pathways. The common view on qualitative interaction and activation patterns of the three subclasses, the BH3-only proteins, prosurvivals, and effectors, is static and currently being revolutionized by an emerging understanding of the complex dynamic equilibria that govern cellular fate. Recent experimental evidence on protein associations with the mitochondrial outer membrane, retrotranslocation to the cytosol, and differential binding affinities in aqueous and membranous environments instigate the development of a revised model of Bcl-2 family interplay. Likely, the dynamic processes and their respective timescales need to be taken into account to authentically understand and, by extension, to generate reliable predictions on cellular decision-making. Here, we review the quantitative aspects of Bcl-2 family-regulated MOMP. In particular, we discuss affinity binding constants of protein-protein associations and velocities of post-translational modifications, membrane (retro-) translocations, and effector oligomerization. Moreover, we provide insights into how these kinetic and network information enable systems biological approaches, further enhancing our understanding of the complex molecular mechanisms governing MOMP.

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Measurement of BH3-only protein tolerance

Cited by 22 publications

References 59 publications

MiR-35 buffers apoptosis thresholds in the C. elegans germline by antagonizing both MAPK and core apoptosis pathways

MiR-35 buffers apoptosis thresholds in the C. elegans germline by antagonizing both MAPK and core apoptosis pathways

KPNB1 inhibition disrupts proteostasis and triggers unfolded protein response-mediated apoptosis in glioblastoma cells

Counting on Death – Quantitative aspects of Bcl‐2 family regulation

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