Fattening the perspective of Hox protein specificity through SLiMming

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.

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.


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.


BMC Genomics ◽  
2008 ◽  
Vol 9 (1) ◽  
pp. 452 ◽  
Author(s):  
Siyuan Ren ◽  
Guang Yang ◽  
Youyu He ◽  
Yiguo Wang ◽  
Yixue Li ◽  
...  

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.


PLoS Genetics ◽  
2011 ◽  
Vol 7 (10) ◽  
pp. e1002302 ◽  
Author(s):  
Samir Merabet ◽  
Isma Litim-Mecheri ◽  
Daniel Karlsson ◽  
Richa Dixit ◽  
Mehdi Saadaoui ◽  
...  

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

2001 ◽  
Vol 21 (21) ◽  
pp. 7509-7522 ◽  
Author(s):  
Wei-fang Shen ◽  
Keerthi Krishnan ◽  
H. J. Lawrence ◽  
Corey Largman

ABSTRACT Despite the identification of PBC proteins as cofactors that provide DNA affinity and binding specificity for the HOX homeodomain proteins, HOX proteins do not demonstrate robust activity in transient-transcription assays and few authentic downstream targets have been identified for these putative transcription factors. During a search for additional cofactors, we established that each of the 14 HOX proteins tested, from 11 separate paralog groups, binds to CBP or p300. All six isolated homeodomain fragments tested bind to CBP, suggesting that the homeodomain is a common site of interaction. Surprisingly, CBP-p300 does not form DNA binding complexes with the HOX proteins but instead prevents their binding to DNA. The HOX proteins are not substrates for CBP histone acetyltransferase (HAT) but instead inhibit the activity of CBP in both in vitro and in vivo systems. These mutually inhibitory interactions are reflected by the inability of CBP to potentiate the low levels of gene activation induced by HOX proteins in a range of reporter assays. We propose two models for HOX protein function: (i) HOX proteins may function without CBP HAT to regulate transcription as cooperative DNA binding molecules with PBX, MEIS, or other cofactors, and (ii) the HOX proteins may inhibit CBP HAT activity and thus function as repressors of gene transcription.


2020 ◽  
Author(s):  
Evelyn Ramberger ◽  
Valeria Sapozhnikova ◽  
Elisabeth Kowenz-Leutz ◽  
Karin Zimmermann ◽  
Nathalie Nicot ◽  
...  

AbstractThe pioneering transcription factor C/EBPα coordinates cell fate and cell differentiation. C/EBPα represents an intrinsically disordered protein with multiple short linear motifs and extensive post-translational side chain modifications (PTM), reflecting its modularity and functional plasticity. Here, we combined arrayed peptide matrix screening (PRISMA) with biotin ligase proximity labeling proteomics (BioID) to generate a linear, isoform specific and PTM-dependent protein interaction map of C/EBPα in myeloid cells. The C/EBPα interactome comprises promiscuous and PTM-regulated interactions with protein machineries involved in gene expression, epigenetics, genome organization, DNA replication, RNA processing, and nuclear transport as the basis of functional C/EBPα plasticity. Protein interaction hotspots were identified that coincide with homologous conserved regions of the C/EBP family and revealed interaction motifs that score as molecular recognition features (MoRF). PTMs alter the interaction spectrum of multi-valent C/EBP-motifs to configure a multimodal transcription factor hub that allows interaction with multiple co-regulatory components, including BAF/SWI-SNF or Mediator complexes. Combining PRISMA and BioID acts as a powerful strategy to systematically explore the interactomes of intrinsically disordered proteins and their PTM-regulated, multimodal capacity.Key pointsIntegration of proximity labeling and arrayed peptide screen proteomics refines the interactome of C/EBPα isoformsHotspots of protein interactions in C/EBPα mostly occur in conserved short linear motifsInteractions of the BAF/SWI-SNF complex with C/EBPα are modulated by arginine methylation and isoform statusThe integrated experimental strategy suits systematic interactome studies of intrinsically disordered proteins


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