scholarly journals The X-linked intellectual disability gene product and E3 ubiquitin ligase KLHL15 degrades  doublecortin proteins to constrain neuronal dendritogenesis

2020 ◽  
pp. jbc.RA120.016210
Author(s):  
Jianing Song ◽  
Ronald A. Merrill ◽  
Andrew Y. Usachev ◽  
Stefan Strack
Keyword(s):  
Intellectual Disability ◽  
Brain Development ◽  
Ubiquitin Ligase ◽  
Hippocampal Neurons ◽  
E3 Ubiquitin Ligase ◽  
Gene Mutations ◽  
Disease Protein ◽  
Associated Proteins ◽  
Interaction Regions ◽  
And Function

Proper brain development and function requires finely controlled mechanisms for protein turnover and disruption of genes involved in proteostasis is a common cause of neurodevelopmental disorders. Kelch-like 15 (KLHL15) is a substrate adaptor for cullin3 (Cul3)-containing E3 ubiquitin ligases and KLHL15 gene mutations were recently described as a cause of severe X-linked intellectual disability (XLID). Here, we used a bioinformatics approach to identify a family of neuronal microtubule-associated proteins (MAPs) as KLHL15 substrates, which are themselves critical for early brain development. We biochemically validated doublecortin (DCX), also an X-linked disease protein, and doublecortin-like kinase 1 and 2 (DCLK1/2) as bona fide KLHL15 interactors and mapped KLHL15 interaction regions to their tandem DCX domains. Shared with two previously identified KLHL15 substrates, a FRY tripeptide at the C-terminal edge of the second DCX domain is necessary for KLHL15-mediated ubiquitination of DCX and DCLK1/2 and subsequent proteasomal degradation. Conversely, silencing endogenous KLHL15 markedly stabilizes these DCX domain-containing proteins and prolongs their half-life. Functionally, overexpression of KLHL15 in the presence of wild-type DCX reduces dendritic complexity of cultured hippocampal neurons, whereas neurons expressing FRY-mutant DCX are resistant to KLHL15. Collectively, our findings highlight the critical importance of the E3 ubiquitin ligase adaptor KLHL15 in proteostasis of neuronal MAPs and identify a regulatory network important for development of the mammalian nervous system.

scholarly journals The X-linked intellectual disability gene product and E3 ubiquitin ligase KLHL15 degrades doublecortin proteins to constrain neuronal dendritogenesis

2020 ◽  
Author(s):  
Jianing Song ◽  
Ronald A. Merrill ◽  
Andrew Y. Usachev ◽  
Stefan Strack
Keyword(s):  
Intellectual Disability ◽  
Brain Development ◽  
Ubiquitin Ligase ◽  
Hippocampal Neurons ◽  
E3 Ubiquitin Ligase ◽  
Gene Mutations ◽  
Associated Proteins ◽  
Bona Fide ◽  
Interaction Regions ◽  
And Function

ABSTRACTProper brain development and function requires finely controlled mechanisms for protein turnover and disruption of genes involved in proteostasis is a common cause of neurodevelopmental disorders. Kelch-like 15 (KLHL15) is a substrate adaptor for cullin3 (Cul3)-containing E3 ubiquitin ligases and KLHL15 gene mutations were recently described as a cause of severe X-linked intellectual disability. Here, we used a bioinformatics approach to identify a family of neuronal microtubule-associated proteins (MAPs) as KLHL15 substrates, which are themselves critical for early brain development. We biochemically validated doublecortin (DCX), also an X-linked disease gene, and doublecortin-like kinases 1 and 2 (DCLK1/2) as bona fide KLHL15 interactors and mapped KLHL15 interaction regions to their tandem DCX domains. Shared with two previously identified KLHL15 substrates, a FRY tripeptide at the C-terminal edge of the second DCX domain is necessary for KLHL15-mediated ubiquitination of DCX and DCLK1/2 and subsequent proteasomal degradation. Conversely, silencing endogenous KLHL15 markedly stabilizes these DCX domain-containing proteins and prolongs their half-life. Functionally, overexpression of KLHL15 in the presence of wild-type DCX reduces dendritic complexity of cultured hippocampal neurons, whereas neurons expressing FRY-mutant DCX are resistant to KLHL15. Collectively, our findings highlight the critical importance of the E3 ubiquitin ligase adaptor KLHL15 in proteostasis of neuronal MAPs and identify a regulatory network important for development of the mammalian nervous system.

scholarly journals Molecular basis for the fold organization and sarcomeric targeting of the muscle atrogin MuRF1

Open Biology ◽  
2014 ◽  
Vol 4 (3) ◽  
pp. 130172 ◽  
Author(s):  
Barbara Franke ◽  
Alexander Gasch ◽  
Dayté Rodriguez ◽  
Mohamed Chami ◽  
Muzamil M. Khan ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Quaternary Structure ◽  
E3 Ubiquitin Ligase ◽  
Coiled Coil ◽  
Trim Protein ◽  
Muscle Catabolism ◽  
And Function ◽  
Helical Region ◽  
Structural Significance

MuRF1 is an E3 ubiquitin ligase central to muscle catabolism. It belongs to the TRIM protein family characterized by a tripartite fold of RING, B-box and coiled-coil (CC) motifs, followed by variable C-terminal domains. The CC motif is hypothesized to be responsible for domain organization in the fold as well as for high-order assembly into functional entities. But data on CC from this family that can clarify the structural significance of this motif are scarce. We have characterized the helical region from MuRF1 and show that, contrary to expectations, its CC domain assembles unproductively, being the B2- and COS-boxes in the fold (respectively flanking the CC) that promote a native quaternary structure. In particular, the C-terminal COS-box seemingly forms an α-hairpin that packs against the CC, influencing its dimerization. This shows that a C-terminal variable domain can be tightly integrated within the conserved TRIM fold to modulate its structure and function. Furthermore, data from transfected muscle show that in MuRF1 the COS-box mediates the in vivo targeting of sarcoskeletal structures and points to the pharmacological relevance of the COS domain for treating MuRF1-mediated muscle atrophy.

scholarly journals Structure and function of E3 ubiquitin ligase mindbomb RING domain

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Robert D Wardlow ◽  
Sung Hee Choi ◽  
Brian McMillan ◽  
Stephen C Blacklow
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Structure And Function ◽  
Ring Domain ◽  
And Function

scholarly journals Structure and function of Parkin E3 ubiquitin ligase reveals aspects of RING and HECT ligases

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
B.E. Riley ◽  
J.C. Lougheed ◽  
K. Callaway ◽  
M. Velasquez ◽  
E. Brecht ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Structure And Function ◽  
And Function

Nuclear Lamins: Laminopathies and Their Role in Premature Ageing

2006 ◽  
Vol 86 (3) ◽  
pp. 967-1008 ◽  
Author(s):  
J. L. V. Broers ◽  
F. C. S. Ramaekers ◽  
G. Bonne ◽  
R. Ben Yaou ◽  
C. J. Hutchison
Keyword(s):  
Transcriptional Control ◽  
Current Knowledge ◽  
Gene Mutations ◽  
Muscular Diseases ◽  
Nuclear Lamins ◽  
Premature Ageing ◽  
The Family ◽  
Associated Proteins ◽  
Cellular Ageing ◽  
And Function

It has been demonstrated that nuclear lamins are important proteins in maintaining cellular as well as nuclear integrity, and in maintaining chromatin organization in the nucleus. Moreover, there is growing evidence that lamins play a prominent role in transcriptional control. The family of laminopathies is a fast-growing group of diseases caused by abnormalities in the structure or processing of the lamin A/C ( LMNA) gene. Mutations or incorrect processing cause more than a dozen different inherited diseases, ranging from striated muscular diseases, via fat- and peripheral nerve cell diseases, to progeria. This broad spectrum of diseases can only be explained if the responsible A-type lamin proteins perform multiple functions in normal cells. This review gives an overview of current knowledge on lamin structure and function and all known diseases associated with LMNA abnormalities. Based on the knowledge of the different functions of A-type lamins and associated proteins, explanations for the observed phenotypes are postulated. It is concluded that lamins seem to be key players in, among others, controlling the process of cellular ageing, since disturbance in lamin protein structure gives rise to several forms of premature ageing.

scholarly journals Functional diversification of Ser-Arg rich protein kinases to control ubiquitin-dependent neurodevelopmental signalling

2020 ◽  
Author(s):  
Francisco Bustos ◽  
Anna Segarra-Fas ◽  
Gino Nardocci ◽  
Andrew Cassidy ◽  
Odetta Antico ◽  
...  
Keyword(s):  
Gene Expression ◽  
Intellectual Disability ◽  
Protein Kinases ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Point Mutations ◽  
Embryonic Stem ◽  
Mrna Splicing ◽  
Cellular Functions ◽  
Functional Diversification

SUMMARYConserved protein kinases with core cellular functions have been frequently redeployed during metazoan evolution to regulate specialized developmental processes. Ser-Arg Repeat Protein Kinase (SRPK) is one such conserved eukaryotic kinase, which controls mRNA splicing. Surprisingly, we show that SRPK has acquired a novel function in regulating a neurodevelopmental ubiquitin signalling pathway. In mammalian embryonic stem cells, SRPK phosphorylates Ser-Arg motifs in RNF12/RLIM, a key developmental E3 ubiquitin ligase that is mutated in an intellectual disability syndrome. Processive phosphorylation by SRPK stimulates RNF12-dependent ubiquitylation of transcription factor substrates, thereby acting to restrain a neural gene expression programme that is aberrantly expressed in intellectual disability. SRPK family genes are also mutated in intellectual disability disorders, and patient-derived SRPK point mutations impair RNF12 phosphorylation. Our data reveal unappreciated functional diversification of SRPK to regulate ubiquitin signalling that ensures correct regulation of neurodevelopmental gene expression.

scholarly journals A novel RLIM/RNF12 variant disrupts protein stability and function to cause severe Tonne-Kalscheuer syndrome

2020 ◽  
Author(s):  
Francisco Bustos ◽  
Carmen Espejo-Serrano ◽  
Anna Segarra-Fas ◽  
Alison J. Eaton ◽  
Kristin D. Kernohan ◽  
...  
Keyword(s):  
X Chromosome ◽  
Ubiquitin Ligase ◽  
Diaphragmatic Hernia ◽  
E3 Ubiquitin Ligase ◽  
Embryonic Stem ◽  
Missense Variant ◽  
X Chromosome Inactivation ◽  
Severe Form ◽  
Chromosome Inactivation ◽  
And Function

ABSTRACTTonne-Kalscheuer syndrome (TOKAS) is an X-linked intellectual disability syndrome associated with variable clinical features including craniofacial abnormalities, hypogenitalism and diaphragmatic hernia. TOKAS is caused exclusively by variants in the gene encoding the E3 ubiquitin ligase gene RLIM, also known as. Here we report identification of a novel RLIM missense variant, c.1262A>G p.(Tyr421Cys) adjacent to the regulatory basic region, which causes a severe form of TOKAS resulting in perinatal lethality by diaphragmatic hernia. Inheritance and X-chromosome inactivation patterns implicate RLIM p.(Tyr421Cys) as the likely pathogenic variant in the affected individual and within the kindred. We show that the RLIM p.(Tyr421Cys) variant disrupts both expression and function of the protein in an embryonic stem cell model. RLIM p.(Tyr421Cys) is correctly localised to the nucleus, but is readily degraded by the proteasome. The RLIM p.(Tyr421Cys) variant also displays significantly impaired E3 ubiquitin ligase activity, which interferes with RLIM function in Xist long-non-coding RNA induction that initiates imprinted X-chromosome inactivation. Our data uncover a highly disruptive missense variant in RLIM that causes a severe form of TOKAS, thereby expanding our understanding of the molecular and phenotypic spectrum of disease severity.

scholarly journals Effect of SUMO-SIM Interaction on the ICP0-Mediated Degradation of PML Isoform II and Its Associated Proteins in Herpes Simplex Virus 1 Infection

2020 ◽  
Vol 94 (12) ◽  
Author(s):  
Behdokht Jan Fada ◽  
Elie Kaadi ◽  
Subodh Kumar Samrat ◽  
Yi Zheng ◽  
Haidong Gu
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Nuclear Bodies ◽  
Lytic Cycle ◽  
Herpes Simplex Virus 1 ◽  
Associated Proteins ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT ND10 nuclear bodies, as part of the intrinsic defenses, impose repression on incoming DNA. Infected cell protein 0 (ICP0), an E3 ubiquitin ligase of herpes simplex virus 1 (HSV-1), can derepress viral genes by degrading ND10 organizers to disrupt ND10. These events are part of the initial tug of war between HSV-1 and host, which determines the ultimate outcome of infection. Previously, we reported that ICP0 differentially recognizes promyelocytic leukemia (PML) isoforms. ICP0 depends on a SUMO-interaction motif located at residues 362 to 364 (SIM362-364) to trigger the degradation of PML isoforms II, IV, and VI, while using a bipartite sequence flanking the RING domain to degrade PML I. In this study, we investigated how the SUMO-SIM interaction regulates the degradation of PML II and PML II-associated proteins in ND10. We found that (i) the same regulatory mechanism for PML II degradation was detected in cells permissive or nonpermissive to the ICP0-null virus; (ii) the loss of a single SIM362-364 motif was restored by the presence of four consecutive SIMs from RNF4, but was not rescued by only two of the RNF4 SIMs; (iii) the loss of three C-terminal SIMs of ICP0 was fully restored by four RNF4 SIMs and also partially rescued by two RNF4 SIMs; and (iv) a PML II mutant lacking both lysine SUMOylation and SIM was not recognized by ICP0 for degradation, but was localized to ND10 and mitigated the degradation of other ND10 components, leading to delayed viral production. Taken together, SUMO regulates ICP0 substrate recognition via multiple fine-tuned mechanisms in HSV-1 infection. IMPORTANCE HSV-1 ICP0 is a multifunctional immediate early protein key to effective replication in the HSV-1 lytic cycle and reactivation in the latent cycle. ICP0 transactivates gene expression by orchestrating an overall mitigation in host intrinsic/innate restrictions. How ICP0 coordinates its multiple active domains and its diverse protein-protein interactions is a key question in understanding the HSV-1 life cycle and pathogenesis. The present study focuses on delineating the regulatory effects of the SUMO-SIM interaction on ICP0 E3 ubiquitin ligase activity regarding PML II degradation. For the first time, we discovered the importance of multivalency in the PML II-ICP0 interaction network and report the involvement of different regulatory mechanisms in PML II recognition by ICP0 in HSV-1 infection.

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