scholarly journals Proteomic analysis identifies novel binding partners of BAP1

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257688
Author(s):  
Roy Baas ◽  
Fenna J. van der Wal ◽  
Onno B. Bleijerveld ◽  
Haico van Attikum ◽  
Titia K. Sixma

BRCA1-associated protein 1 (BAP1) is a tumor suppressor and its loss can result in mesothelioma, uveal and cutaneous melanoma, clear cell renal cell carcinoma and bladder cancer. BAP1 is a deubiquitinating enzyme of the UCH class that has been implicated in various cellular processes like cell growth, cell cycle progression, ferroptosis, DNA damage response and ER metabolic stress response. ASXL proteins activate BAP1 by forming the polycomb repressive deubiquitinase (PR-DUB) complex which acts on H2AK119ub1. Besides the ASXL proteins, BAP1 is known to interact with an established set of additional proteins. Here, we identify novel BAP1 interacting proteins in the cytoplasm by expressing GFP-tagged BAP1 in an endogenous BAP1 deficient cell line using affinity purification followed by mass spectrometry (AP-MS) analysis. Among these novel interacting proteins are Histone acetyltransferase 1 (HAT1) and all subunits of the heptameric coat protein complex I (COPI) that is involved in vesicle formation and protein cargo binding and sorting. We validate that the HAT1 and COPI interactions occur at endogenous levels but find that this interaction with COPI is not mediated through the C-terminal KxKxx cargo sorting signals of the COPI complex.

2021 ◽  
Author(s):  
Roy Baas ◽  
Fenna J. van der Wal ◽  
Onno B. Bleijerveld ◽  
Haico van Attikum ◽  
Titia K. Sixma

AbstractBRCA1-associated protein 1 (BAP1) is a tumor suppressor and its loss can result in mesothelioma, uveal and cutaneous melanoma, clear cell renal cell carcinoma and bladder cancer. BAP1 is a deubiquitinating enzyme of the UCH class that has been implicated in various cellular processes like cell growth, cell cycle progression, ferroptosis and ER metabolic stress response. ASXL proteins activate BAP1 by forming the polycomb repressive deubiquitinase (PR-DUB) complex which acts on H2AK119ub1. Besides the ASXL proteins, BAP1 is known to interact with an established set of additional proteins.Here, we identify novel BAP1 interacting proteins in the cytoplasm by expressing GFP-tagged BAP1 in an endogenous BAP1 deficient cell line using affinity purification followed by mass spectrometry (AP-MS) analysis. Among these novel interacting proteins are Histone acetyltransferase 1 (HAT1) and all subunits of the heptameric coat protein complex I (COPI) that is involved in vesicle formation and protein cargo binding and sorting. We validate that the HAT1 and COPI interactions occur at endogenous levels but find that this interaction with COPI is not mediated through the C-terminal KxKxx cargo sorting signals of the COPI complex.


Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1661-1672 ◽  
Author(s):  
Matt Kaeberlein ◽  
Alex A Andalis ◽  
Gregory B Liszt ◽  
Gerald R Fink ◽  
Leonard Guarente

AbstractThe SSD1 gene of Saccharomyces cerevisiae is a polymorphic locus that affects diverse cellular processes including cell integrity, cell cycle progression, and growth at high temperature. We show here that the SSD1-V allele is necessary for cells to achieve extremely long life span. Furthermore, addition of SSD1-V to cells can increase longevity independently of SIR2, although SIR2 is necessary for SSD1-V cells to attain maximal life span. Past studies of yeast aging have been performed in short-lived ssd1-d strain backgrounds. We propose that SSD1-V defines a previously undescribed pathway affecting cellular longevity and suggest that future studies on longevity-promoting genes should be carried out in long-lived SSD1-V strains.


2018 ◽  
Vol 29 (19) ◽  
pp. 2280-2291 ◽  
Author(s):  
Michele Haltiner Jones ◽  
Eileen T. O’Toole ◽  
Amy S. Fabritius ◽  
Eric G. Muller ◽  
Janet B. Meehl ◽  
...  

Phosphorylation modulates many cellular processes during cell cycle progression. The yeast centrosome (called the spindle pole body, SPB) is regulated by the protein kinases Mps1 and Cdc28/Cdk1 as it nucleates microtubules to separate chromosomes during mitosis. Previously we completed an SPB phosphoproteome, identifying 297 sites on 17 of the 18 SPB components. Here we describe mutagenic analysis of phosphorylation events on Spc29 and Spc42, two SPB core components that were shown in the phosphoproteome to be heavily phosphorylated. Mutagenesis at multiple sites in Spc29 and Spc42 suggests that much of the phosphorylation on these two proteins is not essential but enhances several steps of mitosis. Of the 65 sites examined on both proteins, phosphorylation of the Mps1 sites Spc29-T18 and Spc29-T240 was shown to be critical for function. Interestingly, these two sites primarily influence distinct successive steps; Spc29-T240 is important for the interaction of Spc29 with Spc42, likely during satellite formation, and Spc29-T18 facilitates insertion of the new SPB into the nuclear envelope and promotes anaphase spindle elongation. Phosphorylation sites within Cdk1 motifs affect function to varying degrees, but mutations only have significant effects in the presence of an MPS1 mutation, supporting a theme of coregulation by these two kinases.


2020 ◽  
Vol 52 (10) ◽  
pp. 1637-1651 ◽  
Author(s):  
Sang-Min Jang ◽  
Christophe E. Redon ◽  
Bhushan L. Thakur ◽  
Meriam K. Bahta ◽  
Mirit I. Aladjem

Abstract The last decade has revealed new roles for Cullin-RING ubiquitin ligases (CRLs) in a myriad of cellular processes, including cell cycle progression. In addition to CRL1, also named SCF (SKP1-Cullin 1-F box protein), which has been known for decades as an important factor in the regulation of the cell cycle, it is now evident that all eight CRL family members are involved in the intricate cellular pathways driving cell cycle progression. In this review, we summarize the structure of CRLs and their functions in driving the cell cycle. We focus on how CRLs target key proteins for degradation or otherwise alter their functions to control the progression over the various cell cycle phases leading to cell division. We also summarize how CRLs and the anaphase-promoting complex/cyclosome (APC/C) ligase complex closely cooperate to govern efficient cell cycle progression.


2020 ◽  
Vol 21 (3) ◽  
pp. 1106 ◽  
Author(s):  
Sruthi V. Hindupur ◽  
Sebastian C. Schmid ◽  
Jana Annika Koch ◽  
Ahmed Youssef ◽  
Eva-Maria Baur ◽  
...  

The JAK-STAT signalling pathway regulates cellular processes like cell division, cell death and immune regulation. Dysregulation has been identified in solid tumours and STAT3 activation is a marker for poor outcome. The aim of this study was to explore potential therapeutic strategies by targeting this pathway in bladder cancer (BC). High STAT3 expression was detected in 51.3% from 149 patient specimens with invasive bladder cancer by immunohistochemistry. Protein expression of JAK, STAT and downstream targets were confirmed in 10 cell lines. Effects of the JAK inhibitors Ruxolitinib and BSK-805, and STAT3/5 inhibitors Stattic, Nifuroxazide and SH-4-54 were analysed by cell viability assays, immunoblotting, apoptosis and cell cycle progression. Treatment with STAT3/5 but not JAK1/2 inhibitors reduced survival, levels of phosphorylated STAT3 and Cyclin-D1 and increased apoptosis. Tumour xenografts, using the chicken chorioallantoic membrane (CAM) model responded to Stattic monotherapy. Combination of Stattic with Cisplatin, Docetaxel, Gemcitabine, Paclitaxel and CDK4/6 inhibitors showed additive effects. The combination of Stattic with the oncolytic adenovirus XVir-N-31 increased viral replication and cell lysis. Our results provide evidence that inhibitors against STAT3/5 are promising as novel mono- and combination therapy in bladder cancer.


2019 ◽  
Vol 20 (19) ◽  
pp. 4852 ◽  
Author(s):  
Junjun Wang ◽  
Juanjuan Liu ◽  
Xinmiao Ji ◽  
Xin Zhang

STK16, reported as a Golgi localized serine/threonine kinase, has been shown to participate in multiple cellular processes, including the TGF-β signaling pathway, TGN protein secretion and sorting, as well as cell cycle and Golgi assembly regulation. However, the mechanisms of the regulation of its kinase activity remain underexplored. It was known that STK16 is autophosphorylated at Thr185, Ser197, and Tyr198 of the activation segment in its kinase domain. We found that STK16 localizes to the cell membrane and the Golgi throughout the cell cycle, but mutations in the auto-phosphorylation sites not only alter its subcellular localization but also affect its kinase activity. In particular, the Tyr198 mutation alone significantly reduced the kinase activity of STK16, abolished its Golgi and membrane localization, and affected the cell cycle progression. This study demonstrates that a single site autophosphorylation of STK16 could affect its localization and function, which provides insights into the molecular regulatory mechanism of STK16’s kinase activity.


2005 ◽  
Vol 33 (4) ◽  
pp. 609-613 ◽  
Author(s):  
A. Grande-García ◽  
A. Echarri ◽  
M.A. Del Pozo

Integrins are crucial regulators of essential cellular processes such as gene expression, cell proliferation and migration. Alteration of these processes is central to tumourigenesis. Integrin signals mediate anchorage dependence of cell growth, while growth of cancer cells is anchorage-independent. Integrins critically regulate Rho family GTPases, that are also involved in cell-cycle progression and oncogenesis. In addition to their effect on GTP loading, integrins independently control the translocation of GTP-bound Rac to the plasma membrane. This step is essential for Rac binding to effectors. Integrins increase membrane affinity for Rac, leading to RhoGDI dissociation and effector coupling locally, in the vicinity of activated/bound integrins. Integrin-regulated Rac binding sites are within CEMMs (cholesterol-enriched membrane microdomains). Integrins control Rac signalling by preventing the internalization of its binding sites in CEMMs. Integrin regulation of signalling pathways initiated in CEMMs may be important for the spatial control of cell migration and anchorage dependence of cell growth.


Botany ◽  
2011 ◽  
Vol 89 (3) ◽  
pp. 175-190 ◽  
Author(s):  
Aaron D. Johnstone ◽  
Robert T. Mullen ◽  
Dev Mangroo

Nuclear tRNA export plays an essential role in several key cellular processes, such as regulation of protein synthesis, cell cycle progression, response to nutrient availability and DNA damage, and development. While the overall mechanism of nuclear tRNA export is, in general, poorly understood, the details of specific steps are emerging from studies conducted in different organisms aimed at identifying and characterizing components involved in the process. Here, we report that Arabidopsis thaliana (L.) Heynh At2g40730 encodes CTEXP, a cytoplasmic protein component of the nuclear tRNA export process. CTEXP bound tRNA directly and saturably, and like the nuclear tRNA export receptor PAUSED, overexpression of CTEXP restored export of a nuclear export-defective lysine amber suppressor tRNA in tobacco cells. CTEXP was also found to associate with nucleoporins of the nuclear pore complex (NPC), PAUSED, and the GTPase Ran in vivo. CTEXP interacted directly with PAUSED in vitro and RanGTP, but not RanGDP. Furthermore, a portion of CTEXP appeared to associate with the NPC. Taken together, the data suggest that CTEXP assists with unloading of tRNAs from PAUSED at the cytoplasmic side of the NPC in plant cells.


2020 ◽  
Author(s):  
Joseph A. Brazzo ◽  
Kwonmoo Lee ◽  
Yongho Bae

SUMMARYCells exhibit pathological behaviors in response to increased extracellular matrix (ECM) stiffness, including accelerated cell proliferation and migration [1–9], which are correlated with increased intracellular stiffness and tension [2, 3, 10–12]. The biomechanical signal transduction of ECM stiffness into relevant molecular signals and resultant cellular processes is mediated through multiple proteins associated with the actin cytoskeleton in lamellipodia [2, 3, 10, 11, 13]. However, the molecular mechanisms by which lamellipodial dynamics regulate cellular responses to ECM stiffening remain unclear. Previous work described that lamellipodin, a phosphoinositide- and actin filament-binding protein that is known mostly for controlling cell migration [14–21], promotes ECM stiffness-mediated early cell cycle progression [2], revealing a potential commonality between the mechanisms controlling stiffness-dependent cell migration and those controlling cell proliferation. However, i) whether and how ECM stiffness affects the levels of lamellipodin expression and ii) whether stiffness-mediated lamellipodin expression is required throughout cell cycle progression and for intracellular stiffness have not been explored. Here, we show that the levels of lamellipodin expression in cells are significantly increased by a stiff ECM and that this stiffness-mediated lamellipodin upregulation persistently stimulates cell cycle progression and intracellular stiffness throughout the cell cycle, from the early G1 phase to M phase. Finally, we show that both Rac activation and intracellular stiffening are required for the mechanosensitive induction of lamellipodin. More specifically, inhibiting Rac1 activation in cells on stiff ECM reduces the levels of lamellipodin expression, and this effect is reversed by the overexpression of activated Rac1 in cells on soft ECM. We thus propose that lamellipodin is a critical molecular lynchpin in the control of mechanosensitive cell cycle progression and intracellular stiffness.


2021 ◽  
Vol 134 (9) ◽  
Author(s):  
Abigail Allen ◽  
David Gau ◽  
Partha Roy

ABSTRACT Dynamic remodeling of the actin cytoskeleton is an essential feature for virtually all actin-dependent cellular processes, including cell migration, cell cycle progression, chromatin remodeling and gene expression, and even the DNA damage response. An altered actin cytoskeleton is a structural hallmark associated with numerous pathologies ranging from cardiovascular diseases to immune disorders, neurological diseases and cancer. The actin cytoskeleton in cells is regulated through the orchestrated actions of a myriad of actin-binding proteins. In this Review, we provide a brief overview of the structure and functions of the actin-monomer-binding protein profilin-1 (Pfn1) and then discuss how dysregulated expression of Pfn1 contributes to diseases associated with the cardiovascular system.


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