scholarly journals RVBs Are Required for Assembling a Functional TIP60 Complex

2013 ◽  
Vol 33 (6) ◽  
pp. 1164-1174 ◽  
Author(s):  
Sudhakar Jha ◽  
Ashish Gupta ◽  
Ashraf Dar ◽  
Anindya Dutta

RVB1/RVB2 (RuvBL1/RuvBL2 or pontin/reptin) are enigmatic AAA+ATPase proteins that are present in multiple cellular complexes. Although they have been implicated in many cellular functions, the exact molecular function of RVB proteins in the various complexes is not clear. TIP60 complex (TIP60.com) is a tumor suppressor chromatin-remodeling complex containing RVB proteins. RVBs are required for the lysine acetyltransferase activity of TIP60.com but not for that of the pure recombinant TIP60 polypeptide. Here we describe two molecular functions of RVBs in TIP60.com. First, RVBs negate the repression of catalytic activity of TIP60 by another protein in TIP60.com, p400. RVBs competitively displace the SNF2 domain of p400 from the TIP60 polypeptide. In addition RVBs are also required for heat stability of TIP60.com by a p400-independent pathway. RVB1 and RVB2 are redundant with each other for these functions and do not require their ATPase activities. Thus, RVB proteins act as molecular adaptors that can substitute for one another to facilitate the optimal assembly, heat stability, and function of the TIP60 complex.

Author(s):  
Richard W. Baker ◽  
Janice M. Reimer ◽  
Peter J. Carman ◽  
Bengi Turegun ◽  
Tsutomu Arakawa ◽  
...  

Biology Open ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. bio029512 ◽  
Author(s):  
Xin Sun ◽  
Swetansu K. Hota ◽  
Yu-Qing Zhou ◽  
Stefanie Novak ◽  
Dario Miguel-Perez ◽  
...  

Impact ◽  
2018 ◽  
Vol 2018 (3) ◽  
pp. 89-91
Author(s):  
Shin-ichi Tate

The field of molecular biology has provided great insights into the structure and function of key molecules. Thanks to this area of research, we can now grasp the biological details of DNA and have characterised an enormous number of molecules in massive data bases. These 'biological periodic tables' have allowed scientists to connect molecules to particular cellular events, furthering scientific understanding of biological processes. However, molecular biology has yet to answer questions regarding 'higher-order' molecular architecture, such as that of chromatin. Chromatin is the molecular material that serves as the building block for chromosomes, the structures that carry an organism's genetic information inside of the cell's nucleus. Understanding the physical properties of chromatin is crucial in developing a more thorough picture of how chromatin's structure relate to its key cellular functions. Moreover, by establishing a physical model of chromatin, scientists will be able to open the doors into the true inner workings of the cell nucleus. Professor Shin-ichi Tate and his team of researchers at Hiroshima University's Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), are attempting to do just that. Through a five-year grant funded by the Platform for Dynamic Approaches to Living Systems from the Ministry of Education, Culture, Sports, Science and Technology, Tate is aiming to gain a clearer understanding of the structure and dynamics of chromatin.


Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 520
Author(s):  
Wenfeng Nie ◽  
Jinyu Wang

As essential structural components of ATP-dependent chromatin-remodeling complex, the nucleolus-localized actin-related proteins (ARPs) play critical roles in many biological processes. Among them, ARP4 is identified as an integral subunit of chromatin remodeling complex SWR1, which is conserved in yeast, humans and plants. It was shown that RNAi mediated knock-down of Arabidopsis thaliana ARP4 (AtARP4) could affect plant development, specifically, leading to early flowering. However, so far, little is known about how ARP4 functions in the SWR1 complex in plant. Here, we identified a loss-of-function mutant of AtARP4 with a single nucleotide change from glycine to arginine, which had significantly smaller leaf size. The results from the split luciferase complementation imaging (LCI) and yeast two hybrid (Y2H) assays confirmed its physical interaction with the scaffold and catalytic subunit of SWR1 complex, photoperiod-independent early flowering 1 (PIE1). Furthermore, mutation of AtARP4 caused altered transcription response of hundreds of genes, in which the number of up-regulated differentially expressed genes (DEGs) was much larger than those down-regulated. Although most DEGs in atarp4 are related to plant defense and response to hormones such as salicylic acid, overall, it has less overlapping with other swr1 mutants and the hta9 hta11 double-mutant. In conclusion, our results reveal that AtARP4 is important for plant growth and such an effect is likely attributed to its repression on gene expression, typically at defense-related loci, thus providing some evidence for the coordination of plant growth and defense, while the regulatory patterns and mechanisms are distinctive from other SWR1 complex components.


Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1960
Author(s):  
K. Tanuj Sapra ◽  
Ohad Medalia

The cytoskeleton of the eukaryotic cell provides a structural and functional scaffold enabling biochemical and cellular functions. While actin and microtubules form the main framework of the cell, intermediate filament networks provide unique mechanical properties that increase the resilience of both the cytoplasm and the nucleus, thereby maintaining cellular function while under mechanical pressure. Intermediate filaments (IFs) are imperative to a plethora of regulatory and signaling functions in mechanotransduction. Mutations in all types of IF proteins are known to affect the architectural integrity and function of cellular processes, leading to debilitating diseases. The basic building block of all IFs are elongated α-helical coiled-coils that assemble hierarchically into complex meshworks. A remarkable mechanical feature of IFs is the capability of coiled-coils to metamorphize into β-sheets under stress, making them one of the strongest and most resilient mechanical entities in nature. Here, we discuss structural and mechanical aspects of IFs with a focus on nuclear lamins and vimentin.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 336
Author(s):  
Roberta Melchionna ◽  
Paola Trono ◽  
Annalisa Tocci ◽  
Paola Nisticò

Human tissues, to maintain their architecture and function, respond to injuries by activating intricate biochemical and physical mechanisms that regulates intercellular communication crucial in maintaining tissue homeostasis. Coordination of the communication occurs through the activity of different actin cytoskeletal regulators, physically connected to extracellular matrix through integrins, generating a platform of biochemical and biomechanical signaling that is deregulated in cancer. Among the major pathways, a controller of cellular functions is the cytokine transforming growth factor β (TGFβ), which remains a complex and central signaling network still to be interpreted and explained in cancer progression. Here, we discuss the link between actin dynamics and TGFβ signaling with the aim of exploring their aberrant interaction in cancer.


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