scholarly journals Phylogenomics-guided discovery of a novel conserved cassette of short linear motifs in BubR1 essential for the spindle checkpoint

2016 ◽  
Author(s):  
Eelco Tromer ◽  
Debora Bade ◽  
Berend Snel ◽  
Geert J.P.L. Kops

AbstractThe spindle assembly checkpoint (SAC) maintains genomic integrity by preventing progression of mitotic cell division until all chromosomes are stably attached to spindle microtubules. The SAC critically relies on the paralogs Bub1 and BubR1/Mad3, which integrate kinetochore-spindle attachment status with generation of the anaphase inhibitory complex MCC. We previously reported on the widespread occurrences of independent gene duplications of an ancestral ‘MadBub’ gene in eukaryotic evolution and the striking parallel subfunctionalization that lead to loss of kinase function in BubR1/Mad3-like paralogs. We now present an elaborate subfunctionalization analysis that includes all known motifs in Bub1 and BubR1, and show that ancestral features are consistently retained in the same functional paralog: GLEBS/CDI/CDII/kinase in the Bub1-like and KEN1/KEN2/D-Box in the BubR1/Mad3-like. The recently described ABBA motif can be found in either or both paralogs. We however discovered two additional ABBA motifs that flank KEN2. This cassette of ABBA1-KEN2-ABBA2 forms a strictly conserved module in all ancestral and BubR1/Mad3-like proteins, suggestive of a specific and crucial SAC function. Indeed, deletion of the ABBA motifs in human BUBR1 abrogates the SAC and affects APC/C-Cdc20 interactions. Our detailed comparative genomics analyses thus enabled discovery of a conserved cassette of motifs essential for the SAC and shows how this approach can be used to uncover hitherto unrecognized functional protein features.

Open Biology ◽  
2016 ◽  
Vol 6 (12) ◽  
pp. 160315 ◽  
Author(s):  
Eelco Tromer ◽  
Debora Bade ◽  
Berend Snel ◽  
Geert J. P. L. Kops

The spindle assembly checkpoint (SAC) maintains genomic integrity by preventing progression of mitotic cell division until all chromosomes are stably attached to spindle microtubules. The SAC critically relies on the paralogues Bub1 and BubR1/Mad3, which integrate kinetochore–spindle attachment status with generation of the anaphase inhibitory complex MCC. We previously reported on the widespread occurrences of independent gene duplications of an ancestral ‘MadBub’ gene in eukaryotic evolution and the striking parallel subfunctionalization that lead to loss of kinase function in BubR1/Mad3-like paralogues. Here, we present an elaborate subfunctionalization analysis of the Bub1/BubR1 gene family and perform de novo sequence discovery in a comparative phylogenomics framework to trace the distribution of ancestral sequence features to extant paralogues throughout the eukaryotic tree of life. We show that known ancestral sequence features are consistently retained in the same functional paralogue: GLEBS/CMI/CDII/kinase in the Bub1-like and KEN1/KEN2/D-Box in the BubR1/Mad3-like. The recently described ABBA motif can be found in either or both paralogues. We however discovered two additional ABBA motifs that flank KEN2. This cassette of ABBA1-KEN2-ABBA2 forms a strictly conserved module in all ancestral and BubR1/Mad3-like proteins, suggestive of a specific and crucial SAC function. Indeed, deletion of the ABBA motifs in human BUBR1 abrogates the SAC and affects APC/C–Cdc20 interactions. Our detailed comparative genomics analyses thus enabled discovery of a conserved cassette of motifs essential for the SAC and shows how this approach can be used to uncover hitherto unrecognized functional protein features.


2018 ◽  
Vol 62 (11-12) ◽  
pp. 755-766
Author(s):  
Lucrezia Rinaldi ◽  
Andrew J. Saurin ◽  
Yacine Graba

The functional identification and dissection of protein domains has been a successful approach towards the understanding of Hox protein specificity. However, only a few functional protein domains have been identified; this has been a major limitation in deciphering the molecular modalities of Hox protein action. We explore here, by in silico survey of short linear motifs (SLiMs) in Hox proteins, the contribution of SLiMs to Hox proteins, focusing on the mouse, chick and Drosophila Hox complement. Our findings reveal a widespread and uniform distribution of SLiMs along Hox protein sequences and identify the most apparent features of Hox associated SLiMs. While few motifs have been associated with Hox proteins so far, this work suggests that many more contribute to Hox protein functions. The potential and difficulties to apprehend the full contribution of SLiMs in controlling Hox protein functions are discussed.


2018 ◽  
Vol 87 (1) ◽  
pp. 921-964 ◽  
Author(s):  
David L. Brautigan ◽  
Shirish Shenolikar

Protein serine/threonine phosphatases (PPPs) are ancient enzymes, with distinct types conserved across eukaryotic evolution. PPPs are segregated into types primarily on the basis of the unique interactions of PPP catalytic subunits with regulatory proteins. The resulting holoenzymes dock substrates distal to the active site to enhance specificity. This review focuses on the subunit and substrate interactions for PPP that depend on short linear motifs. Insights about these motifs from structures of holoenzymes open new opportunities for computational biology approaches to elucidate PPP networks. There is an expanding knowledge base of posttranslational modifications of PPP catalytic and regulatory subunits, as well as of their substrates, including phosphorylation, acetylation, and ubiquitination. Cross talk between these posttranslational modifications creates PPP-based signaling. Knowledge of PPP complexes, signaling clusters, as well as how PPPs communicate with each other in response to cellular signals should unlock the doors to PPP networks and signaling “clouds” that orchestrate and coordinate different aspects of cell physiology.


2020 ◽  
Vol 64 (2) ◽  
pp. 325-336 ◽  
Author(s):  
Dimitriya H. Garvanska ◽  
Jakob Nilsson

Abstract Kinetochores are instrumental for accurate chromosome segregation by binding to microtubules in order to move chromosomes and by delaying anaphase onset through the spindle assembly checkpoint (SAC). Dynamic phosphorylation of kinetochore components is key to control these activities and is tightly regulated by temporal and spatial recruitment of kinases and phosphoprotein phosphatases (PPPs). Here we focus on PP1, PP2A-B56 and PP2A-B55, three PPPs that are important regulators of mitosis. Despite the fact that these PPPs share a very similar active site, they target unique ser/thr phosphorylation sites to control kinetochore function. Specificity is in part achieved by PPPs binding to short linear motifs (SLiMs) that guide their substrate specificity. SLiMs bind to conserved pockets on PPPs and are degenerate in nature, giving rise to a range of binding affinities. These SLiMs control the assembly of numerous substrate specifying complexes and their position and binding strength allow PPPs to target specific phosphorylation sites. In addition, the activity of PPPs is regulated by mitotic kinases and inhibitors, either directly at the activity level or through affecting PPP–SLiM interactions. Here, we discuss recent progress in understanding the regulation of PPP specificity and activity and how this controls kinetochore biology.


Toxins ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 290
Author(s):  
Caterina Peggion ◽  
Fiorella Tonello

Snake venom phospholipases A2 (PLA2s) have sequences and structures very similar to those of mammalian group I and II secretory PLA2s, but they possess many toxic properties, ranging from the inhibition of coagulation to the blockage of nerve transmission, and the induction of muscle necrosis. The biological properties of these proteins are not only due to their enzymatic activity, but also to protein–protein interactions which are still unidentified. Here, we compare sequence alignments of snake venom and mammalian PLA2s, grouped according to their structure and biological activity, looking for differences that can justify their different behavior. This bioinformatics analysis has evidenced three distinct regions, two central and one C-terminal, having amino acid compositions that distinguish the different categories of PLA2s. In these regions, we identified short linear motifs (SLiMs), peptide modules involved in protein–protein interactions, conserved in mammalian and not in snake venom PLA2s, or vice versa. The different content in the SLiMs of snake venom with respect to mammalian PLA2s may result in the formation of protein membrane complexes having a toxic activity, or in the formation of complexes whose activity cannot be blocked due to the lack of switches in the toxic PLA2s, as the motif recognized by the prolyl isomerase Pin1.


2020 ◽  
Vol 38 (1) ◽  
pp. 113-127 ◽  
Author(s):  
Peter Hraber ◽  
Paul E. O’Maille ◽  
Andrew Silberfarb ◽  
Katie Davis-Anderson ◽  
Nicholas Generous ◽  
...  

2017 ◽  
Vol 24 (9) ◽  
pp. T97-T106 ◽  
Author(s):  
Bing Cheng ◽  
Karen Crasta

Antimicrotubule agents are commonly utilised as front-line therapies against several malignancies, either by themselves or as combination therapies. Cell-based studies have pinpointed the anti-proliferative basis of action to be a consequence of perturbation of microtubule dynamics leading to sustained activation of the spindle assembly checkpoint, prolonged mitotic arrest and mitotic cell death. However, depending on the biological context and cell type, cells may take an alternative route besides mitotic cell death via a process known as mitotic slippage. Here, mitotically arrested cells ‘slip’ to the next interphase without undergoing proper chromosome segregation and cytokinesis. These post-slippage cells in turn have two main cell fates, either cell death or a G1 arrest ensuing in senescence. In this review, we take a look at the factors determining mitotic cell death vs mitotic slippage, post-slippage cell fates and accompanying features, and their consequences for antimicrotubule drug treatment outcomes.


eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Manon Baëza ◽  
Séverine Viala ◽  
Marjorie Heim ◽  
Amélie Dard ◽  
Bruno Hudry ◽  
...  

Hox proteins are well-established developmental regulators that coordinate cell fate and morphogenesis throughout embryogenesis. In contrast, our knowledge of their specific molecular modes of action is limited to the interaction with few cofactors. Here, we show that Hox proteins are able to interact with a wide range of transcription factors in the live Drosophila embryo. In this context, specificity relies on a versatile usage of conserved short linear motifs (SLiMs), which, surprisingly, often restrains the interaction potential of Hox proteins. This novel buffering activity of SLiMs was observed in different tissues and found in Hox proteins from cnidarian to mouse species. Although these interactions remain to be analysed in the context of endogenous Hox regulatory activities, our observations challenge the traditional role assigned to SLiMs and provide an alternative concept to explain how Hox interactome specificity could be achieved during the embryonic development.


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