scholarly journals The E3 Ligase CHIP: Insights into Its Structure and Regulation

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Indranil Paul ◽  
Mrinal K. Ghosh
Keyword(s):  
Quality Control ◽  
Tandem Repeats ◽  
Current Knowledge ◽  
Coiled Coil ◽  
E3 Ligase ◽  
Review Article ◽  
Regulatory Mechanisms ◽  
Carboxy Terminus ◽  
Interacting Protein ◽  
Coiled Coil Region

The carboxy-terminus of Hsc70 interacting protein (CHIP) is a cochaperone E3 ligase containing three tandem repeats of tetratricopeptide (TPR) motifs and a C-terminal U-box domain separated by a charged coiled-coil region. CHIP is known to function as a central quality control E3 ligase and regulates several proteins involved in a myriad of physiological and pathological processes. Recent studies have highlighted varied regulatory mechanisms operating on the activity of CHIP which is crucial for cellular homeostasis. In this review article, we give a concise account of our current knowledge on the biochemistry and regulation of CHIP.

scholarly journals SVIP Is a Novel VCP/p97-interacting Protein Whose Expression Causes Cell Vacuolation

2003 ◽  
Vol 14 (1) ◽  
pp. 262-273 ◽  
Author(s):  
Masami Nagahama ◽  
Mie Suzuki ◽  
Yuko Hamada ◽  
Kiyotaka Hatsuzawa ◽  
Katsuko Tani ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Coiled Coil ◽  
Adaptor Proteins ◽  
Interacting Protein ◽  
Cellular Processes ◽  
Coiled Coil Region ◽  
Acid Protein ◽  
Extensive Cell ◽  
Dependent Protein ◽  
Amino Acid Protein

VCP/p97 is involved in a variety of cellular processes, including membrane fusion and ubiquitin-dependent protein degradation. It has been suggested that adaptor proteins such as p47 and Ufd1p confer functional versatility to VCP/p97. To identify novel adaptors, we searched for proteins that interact specifically with VCP/p97 by using the yeast two-hybrid system, and discovered a novel VCP/p97-interacting protein named smallVCP/p97-interactingprotein (SVIP). Rat SVIP is a 76-amino acid protein that contains two putative coiled-coil regions, and potential myristoylation and palmitoylation sites at the N terminus. Binding experiments revealed that the N-terminal coiled-coil region of SVIP, and the N-terminal and subsequent ATP-binding regions (ND1 domain) of VCP/p97, interact with each other. SVIP and previously identified adaptors p47 and ufd1p interact with VCP/p97 in a mutually exclusive manner. Overexpression of full-length SVIP or a truncated mutant did not markedly affect the structure of the Golgi apparatus, but caused extensive cell vacuolation reminiscent of that seen upon the expression of VCP/p97 mutants or polyglutamine proteins in neuronal cells. The vacuoles seemed to be derived from endoplasmic reticulum membranes. These results together suggest that SVIP is a novelVCP/p97 adaptor whose function is related to the integrity of the endoplasmic reticulum.

scholarly journals Does it take two to tango? RING domain self-association and activity in TRIM E3 ubiquitin ligases

2020 ◽  
Vol 48 (6) ◽  
pp. 2615-2624
Author(s):  
Filippo Fiorentini ◽  
Diego Esposito ◽  
Katrin Rittinger
Keyword(s):  
Coiled Coil ◽  
E3 Ligase ◽  
Protein Family ◽  
Ring Domain ◽  
Cellular Functions ◽  
Protein Activity ◽  
Coiled Coil Region ◽  
Tripartite Motif ◽  
Large Protein Family ◽  
Self Association

TRIM proteins form a protein family that is characterized by a conserved tripartite motif domain comprising a RING domain, one or two B-box domains and a coiled-coil region. Members of this large protein family are important regulators of numerous cellular functions including innate immune responses, transcriptional regulation and apoptosis. Key to their cellular role is their E3 ligase activity which is conferred by the RING domain. Self-association is an important characteristic of TRIM protein activity and is mediated by homodimerization via the coiled-coil region, and in some cases higher order association via additional domains of the tripartite motif. In many of the TRIM family proteins studied thus far, RING dimerization is an important prerequisite for E3 ligase enzymatic activity though the propensity of RING domains to dimerize differs significantly between different TRIMs and can be influenced by other regions of the protein.

scholarly journals MICAL-L1 Links EHD1 to Tubular Recycling Endosomes and Regulates Receptor Recycling

2009 ◽  
Vol 20 (24) ◽  
pp. 5181-5194 ◽  
Author(s):  
Mahak Sharma ◽  
Sai Srinivas Panapakkam Giridharan ◽  
Juliati Rahajeng ◽  
Naava Naslavsky ◽  
Steve Caplan
Keyword(s):  
Coiled Coil ◽  
Live Cells ◽  
Endocytic Recycling ◽  
Interacting Protein ◽  
Recycling Endosomes ◽  
Coiled Coil Region ◽  
Membrane Tubules ◽  
Tubular Membranes

Endocytic recycling of receptors and lipids occurs via a complex network of tubular and vesicular membranes. EHD1 is a key regulator of endocytosis and associates with tubular membranes to facilitate recycling. Although EHD proteins tubulate membranes in vitro, EHD1 primarily associates with preexisting tubules in vivo. How EHD1 is recruited to these tubular endosomes remains unclear. We have determined that the Rab8-interacting protein, MICAL-L1, associates with EHD1, with both proteins colocalizing to long tubular membranes, in vitro and in live cells. MICAL-L1 is a largely uncharacterized member of the MICAL-family of proteins that uniquely contains two asparagine-proline-phenylalanine motifs, sequences that typically interact with EH-domains. Our data show that the MICAL-L1 C-terminal coiled-coil region is necessary and sufficient for its localization to tubular membranes. Moreover, we provide unexpected evidence that endogenous MICAL-L1 can link both EHD1 and Rab8a to these structures, as its depletion leads to loss of the EHD1-Rab8a interaction and the absence of both of these proteins from the membrane tubules. Finally, we demonstrate that MICAL-L1 is essential for efficient endocytic recycling. These data implicate MICAL-L1 as an unusual type of Rab effector that regulates endocytic recycling by recruiting and linking EHD1 and Rab8a on membrane tubules.

scholarly journals Accommodation of structural rearrangements in the huntingtin-interacting protein 1 coiled-coil domain

2010 ◽  
Vol 66 (3) ◽  
pp. 314-318 ◽  
Author(s):  
Jeremy D. Wilbur ◽  
Peter K. Hwang ◽  
Frances M. Brodsky ◽  
Robert J. Fletterick
Keyword(s):  
Light Chain ◽  
Coiled Coil ◽  
Actin Binding ◽  
Interacting Protein ◽  
Similar Region ◽  
Coiled Coil Domain ◽  
Coiled Coil Region ◽  
Huntingtin Interacting Protein 1 ◽  
Conformational Regulation ◽  
Huntingtin Interacting Protein

Huntingtin-interacting protein 1 (HIP1) is an important link between the actin cytoskeleton and clathrin-mediated endocytosis machinery. HIP1 has also been implicated in the pathogenesis of Huntington's disease. The binding of HIP1 to actin is regulated through an interaction with clathrin light chain. Clathrin light chain binds to a flexible coiled-coil domain in HIP1 and induces a compact state that is refractory to actin binding. To understand the mechanism of this conformational regulation, a high-resolution crystal structure of a stable fragment from the HIP1 coiled-coil domain was determined. The flexibility of the HIP1 coiled-coil region was evident from its variation from a previously determined structure of a similar region. A hydrogen-bond network and changes in coiled-coil monomer interaction suggest that the HIP1 coiled-coil domain is uniquely suited to allow conformational flexibility.

scholarly journals PSTPIP: A Tyrosine Phosphorylated Cleavage Furrow–associated Protein that Is a Substrate for a PEST Tyrosine Phosphatase

1997 ◽  
Vol 138 (4) ◽  
pp. 845-860 ◽  
Author(s):  
Susan Spencer ◽  
Donald Dowbenko ◽  
Jill Cheng ◽  
Wenlu Li ◽  
Jennifer Brush ◽  
...  
Keyword(s):  
Tyrosine Phosphatase ◽  
Coiled Coil ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Cleavage Furrow ◽  
Cortical Actin ◽  
Interacting Protein ◽  
Hematopoietic Stem ◽  
Coiled Coil Region ◽  
Negative Effect

We have investigated proteins which interact with the PEST-type protein tyrosine phosphatase, PTP hematopoietic stem cell fraction (HSCF), using the yeast two-hybrid system. This resulted in the identification of proline, serine, threonine phosphatase interacting protein (PSTPIP), a novel member of the actin- associated protein family that is homologous to Schizosaccharomyces pombe CDC15p, a phosphorylated protein involved with the assembly of the actin ring in the cytokinetic cleavage furrow. The binding of PTP HSCF to PSTPIP was induced by a novel interaction between the putative coiled-coil region of PSTPIP and the COOH-terminal, proline-rich region of the phosphatase. PSTPIP is tyrosine phosphorylated both endogenously and in v-Src transfected COS cells, and cotransfection of dominant-negative PTP HSCF results in hyperphosphorylation of PSTPIP. This dominant-negative effect is dependent upon the inclusion of the COOH-terminal, proline-rich PSTPIP-binding region of the phosphatase. Confocal microscopy analysis of endogenous PSTPIP revealed colocalization with the cortical actin cytoskeleton, lamellipodia, and actin-rich cytokinetic cleavage furrow. Overexpression of PSTPIP in 3T3 cells resulted in the formation of extended filopodia, consistent with a role for this protein in actin reorganization. Finally, overexpression of mammalian PSTPIP in exponentially growing S. pombe results in a dominant-negative inhibition of cytokinesis. PSTPIP is therefore a novel actin-associated protein, potentially involved with cytokinesis, whose tyrosine phosphorylation is regulated by PTP HSCF.

scholarly journals Division of Mitochondria Requires a NovelDNM1-interacting Protein, Net2p

2001 ◽  
Vol 12 (2) ◽  
pp. 309-321 ◽  
Author(s):  
Kara L. Cerveny ◽  
J. Michael McCaffery ◽  
Robert E. Jensen
Keyword(s):  
Molecular Mechanisms ◽  
Mitochondrial Fission ◽  
Coiled Coil ◽  
Protein Fluorescence ◽  
Uncharacterized Protein ◽  
Interacting Protein ◽  
Genome Wide ◽  
Coiled Coil Region ◽  
A Genome ◽  
New Gene

Mitochondria are dynamic organelles that undergo frequent division and fusion, but the molecular mechanisms of these two events are not well understood. Dnm1p, a mitochondria-associated, dynamin-related GTPase was previously shown to mediate mitochondrial fission. Recently, a genome-wide yeast two-hybrid screen identified an uncharacterized protein that interacts with Dnm1p. Cells disrupted in this new gene, which we call NET2, contain a single mitochondrion that consists of a network formed by interconnected tubules, similar to the phenotype of dnm1Δ cells. NET2 encodes a mitochondria-associated protein with a predicted coiled-coil region and six WD-40 repeats. Immunofluorescence microscopy indicates that Net2p is located in distinct, dot-like structures along the mitochondrial surface, many of which colocalize with the Dnm1 protein. Fluorescence and immunoelectron microscopy shows that Dnm1p and Net2p preferentially colocalize at constriction sites along mitochondrial tubules. Our results suggest that Net2p is a new component of the mitochondrial division machinery.

scholarly journals Structure of the human C9orf72-SMCR8 complex reveals a multivalent protein interaction architecture

PLoS Biology ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. e3001344
Author(s):  
Julia Nörpel ◽  
Simone Cavadini ◽  
Andreas D. Schenk ◽  
Alexandra Graff-Meyer ◽  
Daniel Hess ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Interacting Protein ◽  
Trimeric Complex ◽  
Cryo Electron Microscopy ◽  
Coiled Coil Region ◽  
C9orf72 Gene ◽  
Cellular Pathways ◽  
Underlying Mechanisms ◽  
Lateral Sclerosis ◽  
Dipeptide Repeat

A major cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) spectrum disorder is the hexanucleotide G4C2 repeat expansion in the first intron of the C9orf72 gene. Many underlying mechanisms lead to manifestation of disease that include toxic gain of function by repeat G4C2 RNAs, dipeptide repeat proteins, and a reduction of the C9orf72 gene product. The C9orf72 protein interacts with SMCR8 and WDR41 to form a trimeric complex and regulates multiple cellular pathways including autophagy. Here, we report the structure of the C9orf72-SMCR8 complex at 3.8 Å resolution using single-particle cryo-electron microscopy (cryo-EM). The structure reveals 2 distinct dimerization interfaces between C9orf72 and SMCR8 that involves an extensive network of interactions. Homology between C9orf72-SMCR8 and Folliculin-Folliculin Interacting Protein 2 (FLCN-FNIP2), a GTPase activating protein (GAP) complex, enabled identification of a key residue within the active site of SMCR8. Further structural analysis suggested that a coiled-coil region within the uDenn domain of SMCR8 could act as an interaction platform for other coiled-coil proteins, and its deletion reduced the interaction of the C9orf72-SMCR8 complex with FIP200 upon starvation. In summary, this study contributes toward our understanding of the biological function of the C9orf72-SMCR8 complex.

scholarly journals Characterisation of class VI TRIM RING domains: linking RING activity to C-terminal domain identity

2019 ◽  
Vol 2 (3) ◽  
pp. e201900295 ◽  
Author(s):  
Rebecca V Stevens ◽  
Diego Esposito ◽  
Katrin Rittinger
Keyword(s):  
Solution Structure ◽  
Coiled Coil ◽  
E3 Ligase ◽  
Cellular Processes ◽  
Terminal Domain ◽  
Coiled Coil Region ◽  
Biochemical Characterisation ◽  
Ring Domains ◽  
Self Association ◽  
Terminal Domains

TRIM E3 ubiquitin ligases regulate multiple cellular processes, and their dysfunction is linked to disease. They are characterised by a conserved N-terminal tripartite motif comprising a RING, B-box domains, and a coiled-coil region, with C-terminal domains often mediating substrate recruitment. TRIM proteins are grouped into 11 classes based on C-terminal domain identity. Class VI TRIMs, TRIM24, TRIM33, and TRIM28, have been described as transcriptional regulators, a function linked to their C-terminal plant homeodomain and bromodomain, and independent of their ubiquitination activity. It is unclear whether E3 ligase activity is regulated in family members where the C-terminal domains function independently. Here, we provide a detailed biochemical characterisation of the RING domains of class VI TRIMs and describe the solution structure of the TRIM28 RING. Our study reveals a lack of activity of the isolated RING domains, which may be linked to the absence of self-association. We propose that class VI TRIMs exist in an inactive state and require additional regulatory events to stimulate E3 ligase activity, ensuring that associated chromatin-remodelling factors are not injudiciously degraded.

scholarly journals The git5 Gβ and git11 Gγ Form an Atypical Gβγ Dimer Acting in the Fission Yeast Glucose/cAMP Pathway

Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1159-1168 ◽  
Author(s):  
Sheila Landry ◽  
Charles S Hoffman
Keyword(s):  
Fission Yeast ◽  
Mammalian Cells ◽  
Glucose Repression ◽  
Coiled Coil ◽  
Carboxy Terminus ◽  
Amino Terminal ◽  
Camp Pathway ◽  
Coiled Coil Domain ◽  
Mutational Activation ◽  
Two Hybrid

AbstractFission yeast adenylate cyclase, like mammalian adenylate cyclases, is regulated by a heterotrimeric G protein. The gpa2 Gα and git5 Gβ are both required for glucose-triggered cAMP signaling. The git5 Gβ is a unique member of the Gβ family in that it lacks an amino-terminal coiled-coil domain shown to be essential for mammalian Gβ folding and interaction with Gγ subunits. Using a git5 bait in a two-hybrid screen, we identified the git11 Gγ gene. Co-immunoprecipitation studies confirm the composition of this Gβγ dimer. Cells deleted for git11 are defective in glucose repression of both fbp1 transcription and sexual development, resembling cells lacking either the gpa2 Gα or the git5 Gβ. Overexpression of the gpa2 Gα partially suppresses loss of either the git5 Gβ or the git11 Gγ, while mutational activation of the Gα fully suppresses loss of either Gβ or Gγ. Deletion of gpa2 (Gα), git5 (Gβ), or git11 (Gγ) confer quantitatively distinct effects on fbp1 repression, indicating that the gpa2 Gα subunit remains partially active in the absence of the Gβγ dimer and that the git5 Gβ subunit remains partially active in the absence of the git11 Gγ subunit. The addition of the CAAX box from the git11 Gγ to the carboxy-terminus of the git5 Gβ partially suppresses the loss of the Gγ. Thus the Gγ in this system is presumably required for localization of the Gβγ dimer but not for folding of the Gβ subunit. In mammalian cells, the essential roles of the Gβ amino-terminal coiled-coil domains and Gγ partners in Gβ folding may therefore reflect a mechanism used by cells that express multiple forms of both Gβ and Gγ subunits to regulate the composition and activity of its G proteins.

scholarly journals Phosphorylation of KLC1 modifies interaction with JIP1 and abolishes the enhanced fast velocity of APP transport by kinesin-1

2017 ◽  
Vol 28 (26) ◽  
pp. 3857-3869 ◽  
Author(s):  
Kyoko Chiba ◽  
Ko-yi Chien ◽  
Yuriko Sobu ◽  
Saori Hata ◽  
Shun Kato ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Amyloid Β ◽  
Tetratricopeptide Repeat ◽  
Amyloid Β Protein ◽  
The Novel ◽  
Anterograde Transport ◽  
Interacting Protein ◽  
Protein Precursor ◽  
Kinesin Light Chain ◽  
Β Protein

In neurons, amyloid β-protein precursor (APP) is transported by binding to kinesin-1, mediated by JNK-interacting protein 1b (JIP1b), which generates the enhanced fast velocity (EFV) and efficient high frequency (EHF) of APP anterograde transport. Previously, we showed that EFV requires conventional interaction between the JIP1b C-terminal region and the kinesin light chain 1 (KLC1) tetratricopeptide repeat, whereas EHF requires a novel interaction between the central region of JIP1b and the coiled-coil domain of KLC1. We found that phosphorylatable Thr466 of KLC1 regulates the conventional interaction with JIP1b. Substitution of Glu for Thr466 abolished this interaction and EFV, but did not impair the novel interaction responsible for EHF. Phosphorylation of KLC1 at Thr466 increased in aged brains, and JIP1 binding to kinesin-1 decreased, suggesting that APP transport is impaired by aging. We conclude that phosphorylation of KLC1 at Thr466 regulates the velocity of transport of APP by kinesin-1 by modulating its interaction with JIP1b.

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