scholarly journals The Ubiquitin versus NEDD8 Binding Preference of NEDD4 Binding Protein 1 (N4BP1) Is Based on a Mutual Conformational Perturbation

2019 ◽  
Author(s):  
Ridvan Nepravishta ◽  
Federica Ferrentino ◽  
Walter Mandaliti ◽  
Anna Mattioni ◽  
Luisa Castagnoli ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Binding Protein ◽  
Functional Characterization ◽  
Binding Domain ◽  
Functional Domain ◽  
Protein Sequence Analysis ◽  
Domain Family ◽  
Hydrophobic Patch ◽  
Binding Domains ◽  
Ubiquitin Binding

Ubiquitin binding domains (UBDs) are modular elements that bind non-covalently to ubiquitin and act as downstream effectors and amplifiers of the ubiquitination signal. With few exceptions, UBDs recognize the hydrophobic path centered on Ile44 (Leu-8, Ile-44, Val-70). Nevertheless, a variety of different orientations, which can be attributed to specific contacts between each UBD and surface residues surrounding the hydrophobic patch, specify how each class of UBD recognizes ubiquitin. Here, we describe the structure of a novel ubiquitin-binding domain that we identified in NEDD4 binding protein 1 (N4BP1). By performing protein sequence analysis, mutagenesis and NMR spectroscopy of the 15N isotopically labelled protein, we demonstrate that a Phe-Pro motif in N4BP1 recognizes the canonical hydrophobic patch of ubiquitin. This recognition mode resembles the molecular mechanism evolved in the CUE (Coupling of ubiquitin conjugation to ER degradation) domain family, where an invariant proline, usually following a phenylalanine, is required for binding to ubiquitin. Interestingly, the UBD of N4BP1 is evolutionary related to CUBAN (Cullin binding domain associating with NEDD8) (40% identity and 47% similarity), a protein module that also recognizes the ubiquitin-like NEDD8, which is the closest relative of ubiquitin (58% identity and 80% similarity). By performing circular dichroism and 15N NMR chemical shift perturbation of N4BP1 in complex with ubiquitin, we demonstrate that the UBD of N4BP1 lacks the NEDD8 binding properties observed in CUBAN and it recognizes the Ile44-centered patch of ubiquitin through a dedicated binding site, which share some of the features observed in the CUE domain family. Moreover, we show that, in addition to mediating the interaction with ubiquitin and ubiquitinated substrates, both the CUBAN and the UBD of N4BP1 are poly-ubiquitinated in cells. This modification is dependent on the presence of a functional domain. We believe that the structural and functional characterization of this novel UBD will allow a deeper understanding of the molecular mechanisms governing N4BP1 function, while at the same time providing a valuable tool for clarifying how the discrimination between ubiquitin and the highly related NEDD8 is achieved.

scholarly journals CoCUN, a Novel Ubiquitin Binding Domain Identified in N4BP1

Biomolecules ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 284 ◽  
Author(s):  
Ridvan Nepravishta ◽  
Federica Ferrentino ◽  
Walter Mandaliti ◽  
Anna Mattioni ◽  
Janine Weber ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Structural Model ◽  
Functional Characterization ◽  
Binding Domain ◽  
15N Nmr ◽  
Protein Sequence Analysis ◽  
Hydrophobic Patch ◽  
Binding Domains ◽  
Ubiquitin Binding ◽  
Ubiquitin Binding Domain

Ubiquitin binding domains (UBDs) are modular elements that bind non-covalently to ubiquitin and act as downstream effectors and amplifiers of the ubiquitination signal. With few exceptions, UBDs recognize the hydrophobic path centered on Ile44, including residues Leu8, Ile44, His68, and Val70. A variety of different orientations, which can be attributed to specific contacts between each UBD and surface residues surrounding the hydrophobic patch, specify how each class of UBD specifically contacts ubiquitin. Here, we describe the structural model of a novel ubiquitin-binding domain that we identified in NEDD4 binding protein 1 (N4BP1). By performing protein sequence analysis, mutagenesis, and nuclear magnetic resonance (NMR) spectroscopy of the 15N isotopically labeled protein, we demonstrate that a Phe-Pro motif in N4BP1 recognizes the canonical hydrophobic patch of ubiquitin. This recognition mode resembles the molecular mechanism evolved in the coupling of ubiquitin conjugation to endoplasmic-reticulum (ER) degradation (CUE) domain family, where an invariant proline, usually following a phenylalanine, is required for ubiquitin binding. Interestingly, this novel UBD, which is not evolutionary related to CUE domains, shares a 40% identity and 47% similarity with cullin binding domain associating with NEDD8 (CUBAN), a protein module that also recognizes the ubiquitin-like NEDD8. Based on these features, we dubbed the region spanning the C-terminal 50 residues of N4BP1 the CoCUN domain, for Cousin of CUBAN. By performing circular dichroism and 15N NMR chemical shift perturbation of N4BP1 in complex with ubiquitin, we demonstrate that the CoCUN domain lacks the NEDD8 binding properties observed in CUBAN. We also show that, in addition to mediating the interaction with ubiquitin and ubiquitinated substrates, both CUBAN and CoCUN are poly-ubiquitinated in cells. The structural and the functional characterization of this novel UBD can contribute to a deeper understanding of the molecular mechanisms governing N4BP1 function, providing at the same time a valuable tool for clarifying how the discrimination between ubiquitin and the highly related NEDD8 is achieved.

scholarly journals Biochemical, Biophysical, and Functional Characterization of Bacterially Expressed and Refolded Receptor Binding Domain ofPlasmodium vivaxDuffy-binding Protein

2001 ◽  
Vol 276 (20) ◽  
pp. 17111-17116 ◽  
Author(s):  
Sanjay Singh ◽  
Kailash Pandey ◽  
Rana Chattopadhayay ◽  
Syed Shams Yazdani ◽  
Andrew Lynn ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Binding Protein ◽  
Functional Characterization ◽  
Binding Domain ◽  
Receptor Binding Domain

scholarly journals Structural Characterization of the Erythrocyte Binding Domain of the Reticulocyte Binding Protein Homologue Family of Plasmodium yoelii

2011 ◽  
Vol 79 (7) ◽  
pp. 2880-2888 ◽  
Author(s):  
Ardina Grüber ◽  
Karthigayan Gunalan ◽  
Jeya Kumar Ramalingam ◽  
Malathy S. S. Manimekalai ◽  
Gerhard Grüber ◽  
...  
Keyword(s):  
Binding Protein ◽  
Intervention Strategy ◽  
Plasmodium Yoelii ◽  
Binding Domain ◽  
Content Type ◽  
Binding Domains ◽  
X Ray Scattering ◽  
Ligand Interactions ◽  
Erythrocyte Binding

ABSTRACTInvasion of the host cell by the malaria parasite is a key step for parasite survival and the only stage of its life cycle where the parasite is extracellular, and it is therefore a target for an antimalaria intervention strategy. Multiple members of the reticulocyte binding protein homologues (RH) family are found in all plasmodia and have been shown to bind to host red blood cells directly. In the study described here, we delineated the erythrocyte binding domain (EBD) of one member of the RH family, termed Py235, fromPlasmodium yoelii. Moreover, we have obtained the low-resolution structure of the EBD using small-angle X-ray scattering. Comparison of the EDB structure to other characterizedPlasmodiumreceptor binding domains suggests that there may be an overall structural conservation. These findings may help in developing new approaches to target receptor ligand interactions mediated by parasite proteins.

scholarly journals Insight into Mammalian Selenocysteine Insertion: Domain Structure and Ribosome Binding Properties of Sec Insertion Sequence Binding Protein 2

2001 ◽  
Vol 21 (5) ◽  
pp. 1491-1498 ◽  
Author(s):  
Paul R. Copeland ◽  
Vincent A. Stepanik ◽  
Donna M. Driscoll
Keyword(s):  
Ribosomal Proteins ◽  
Insertion Sequence ◽  
Rna Binding ◽  
Stop Codon ◽  
Binding Protein ◽  
Binding Domain ◽  
Site Directed Mutagenesis ◽  
Functional Domain ◽  
28S Rrna ◽  
Rna Binding Domain

ABSTRACT The cotranslational incorporation of the unusual amino acid selenocysteine (Sec) into both prokaryotic and eukaryotic proteins requires the recoding of a UGA stop codon as one specific for Sec. The recognition of UGA as Sec in mammalian selenoproteins requires a Sec insertion sequence (SECIS) element in the 3′ untranslated region as well as the SECIS binding protein SBP2. Here we report a detailed analysis of SBP2 structure and function using truncation and site-directed mutagenesis. We have localized the RNA binding domain to a conserved region shared with several ribosomal proteins and eukaryotic translation termination release factor 1. We also identified a separate and novel functional domain N-terminal to the RNA binding domain which was required for Sec insertion but not for SECIS binding. Conversely, we showed that the RNA binding domain was necessary but not sufficient for Sec insertion and that the conserved glycine residue within this domain was required for SECIS binding. Using glycerol gradient sedimentation, we found that SBP2 was stably associated with the ribosomal fraction of cell lysates and that this interaction was not dependent on its SECIS binding activity. This interaction also occurred with purified components in vitro, and we present data which suggest that the SBP2-ribosome interaction occurs via 28S rRNA. SBP2 may, therefore, have a distinct function in selecting the ribosomes to be used for Sec insertion.

scholarly journals MBD3L1 Is a Transcriptional Repressor That Interacts with Methyl-CpG-binding Protein 2 (MBD2) and Components of the NuRD Complex

2004 ◽  
Vol 279 (50) ◽  
pp. 52456-52464 ◽  
Author(s):  
Chun-Ling Jiang ◽  
Seung-Gi Jin ◽  
Gerd P. Pfeifer
Keyword(s):  
Transcriptional Repression ◽  
Binding Protein ◽  
Transcriptional Repressor ◽  
Binding Domain ◽  
Nurd Complex ◽  
Methylated Dna ◽  
Binding Domains ◽  
Mouse Cells

Methyl-CpG-binding domain proteins 2 and 3 (MBD2 and MBD3) are transcriptional repressors that contain methyl-CpG binding domains and are components of a CpG-methylated DNA binding complex named MeCP1. Methyl-CpG-binding protein 3-like 1 (MBD3L1) is a protein with substantial homology to MBD2 and MBD3, but it lacks the methyl-CpG binding domain. MBD3L1 interacts with MBD2 and MBD3in vitroand in yeast two-hybrid assays. Gel shift experiments with a CpG-methylated DNA probe indicate that recombinant MBD3L1 can supershift an MBD2-methylated DNA complex.In vivo, MBD3L1 associates with and colocalizes with MBD2 but not with MBD3 and is recruited to 5-methylcytosine-rich pericentromeric heterochromatin in mouse cells. In glutathioneS-transferase pull-down assays MBD3L1 is found associated with several known components of the MeCP1·NuRD complex, including HDAC1, HDAC2, MTA2, MBD2, RbAp46, and RbAp48, but MBD3 is not found in the MBD3L1-bound fraction. MBD3L1 enhances transcriptional repression of methylated DNA by MBD2. The data are consistent with a role of MBD3L1 as a methylation-dependent transcriptional repressor that may interchange with MBD3 as an MBD2-interacting component of the NuRD complex. MBD3L1 knockout mice were created and were found to be viable and fertile, indicating that MBD3L1 may not be essential or there is functional redundancy (through MBD3) in this pathway. Overall, this study reveals additional complexities in the mechanisms of transcriptional repression by the MBD family proteins.

scholarly journals Oligomerization of Selective Autophagy Receptors for the Targeting and Degradation of Protein Aggregates

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1989
Author(s):  
Wenjun Chen ◽  
Tianyun Shen ◽  
Lijun Wang ◽  
Kefeng Lu
Keyword(s):  
Phase Separation ◽  
Binding Protein ◽  
Protein Aggregates ◽  
Selective Autophagy ◽  
Binding Domains ◽  
Selective Targeting ◽  
Ubiquitin Binding

The selective targeting and disposal of solid protein aggregates are essential for cells to maintain protein homoeostasis. Autophagy receptors including p62, NBR1, Cue5/TOLLIP (CUET), and Tax1-binding protein 1 (TAX1BP1) proteins function in selective autophagy by targeting ubiquitinated aggregates through ubiquitin-binding domains. Here, we summarize previous beliefs and recent findings on selective receptors in aggregate autophagy. Since there are many reviews on selective autophagy receptors, we focus on their oligomerization, which enables receptors to function as pathway determinants and promotes phase separation.

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