Selective Cochlear Degeneration in Mice Lacking the F-Box Protein, Fbx2, a Glycoprotein-Specific Ubiquitin Ligase Subunit

Nelson, Rick F.; Glenn, Kevin A.; Zhang, Yuzhou; Wen, Hsiang; Knutson, Tina; Gouvion, Cynthia M.; Robinson, Barbara K.; Zhou, Zouping; Yang, Baoli; Smith, Richard J.H.; Paulson, Henry L.

doi:10.1523/jneurosci.0206-07.2007

Cited by 72 publications

(68 citation statements)

References 41 publications

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“…41 We and other have reported a similar phenomena with a stable FBG1-Skp1 dimer identified in the mouse cochlea, [30][31][32][33]48 where sequestration by FBG1 likely reduces the level of free Skp1. 33 In the FBG1 knockout mouse, total Skp1 levels are reduced in this tissue, likely to maintain constant levels of free Skp1. By analogy, FBG1 may sequester either Cul7 or APC2 into an inactive complex, allowing the adaptor protein to be present to rapidly bind other available E3 ligase subunits when required.…”

Section: Scf Ubiquitin Ligase Complex (Pdb Code 1ldk) Is Shown For Resupporting

confidence: 65%

“…28 We and others also previously showed that FBG1 had a relatively low affinity for the SCF scaffold protein Cul1; in fact, rather than forming the canonical SCF complex, FBG1 primarily formed a dimer with Skp1. 22,23,[29][30][31][32] Finally we found that FBG1-mediated growth arrest required an intact F box, suggesting that the growth arrest may be mediated through the FBG1-Skp1 interaction.…”

Section: Fbg1 Interacts With Different Cullinmentioning

confidence: 57%

“…In our earlier work we noted that FBG1 had a low affinity for the SCF scaffold protein, Cul1. 22,23,33 In fact, rather than forming the canonical SCF complex, it primarily formed a dimer with Skp1. Since Cul7 is the only other known cullin that binds F-box proteins ( Fig.…”

Section: Fbg1 Interacts With Different Cullinmentioning

confidence: 99%

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FBG1 is a promiscuous ubiquitin ligase that sequesters APC2 and causes S-phase arrest

Wen¹,

Kim

Fuentes

et al. 2010

Cell Cycle

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Section: Scf Ubiquitin Ligase Complex (Pdb Code 1ldk) Is Shown For Resupporting

confidence: 65%

Section: Fbg1 Interacts With Different Cullinmentioning

confidence: 57%

See 1 more Smart Citation

FBG1 is a promiscuous ubiquitin ligase that sequesters APC2 and causes S-phase arrest

Wen¹,

Kim

Fuentes

et al. 2010

Cell Cycle

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“…The SCF E3 ubiquitin ligase complex is widespread in organisms including plants and participates in the process of targeted protein degradation via the 26S proteasome, thereby controlling the compatibility of sexual hybridization between flowering plants (Skowyra et al 1997;Bodine et al 2001;Zheng et al 2002;Cardozo and Pagano 2004;Moon et al 2004;Nelson et al 2007;Xu et al 2013). We therefore investigated the expression patterns and levels of flower associated key genes encoding the subunits of the SCF complex in LA2405 (SI) and P86 (SC) (Fig.…”

Section: Discussionmentioning

confidence: 99%

Insight into flower diversity inSolanum lycopersicumandSolanum chilenseusing comparative biological approaches

et al. 2015

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-X. 2015. Insight into flower diversity in Solanum lycopersicum and Solanum chilense using comparative biological approaches. Can. J. Plant Sci. 95: 467Á478. Flowers, the defining feature of angiosperms, are reproductive organs that enable the continuation and propagation of flowering plant species. However, intra-and inter-species specific reproductive barriers have often evolved in plants; one such example being in the section Lycopersicum of the genus Solanum. This biological phenomenon is closely related to flower diversity, including visible morphologic features and processes such as pollination and fertilization are influenced by floral morphology, although the exact relationships remains unclear. In this study, two distinct Solanum accessions that exhibit either self-compatibility (SC) (S. lycopersicum, P86) or self-incompatibility (SI) (S. chilense, LA2405), from section Lycopersicum in Solanum were subjected to comparative analyses focusing on flower diversity. The long style of LA2405 was found to differ from that of P86 in that it exserts from the anther cone, and the irregular 'long strip' villi on the lower style of LA2405 were structurally distinct from the typical 'finger shape' villi of P86. Pollen grains from both LA2405 and P86 were able to germinate on their own stigmas and those of the other accessions. Pollen tube growth was arrested 1/2 and 3/4 of the way down the style in P86 and LA2405, respectively, when LA2405 was used as pistil parent. Additionally, the disappearance of starch grains and lipid bodies in the cytoplasm of the transmitting tract cells was most evident in cells that were close to the pollen tube. An analysis of the expression of flower associated genes revealed that CUL1 and SLF had an anther-specific expression pattern, while SKP1 and RBX1 were constitutively expressed in flowers of both LA2405 and P86. It was also found that transcript levels of four flower associated genes encoding subunits of the SCF complex (Skp1-Cullin1-F-box-Rbx1) were higher in anthers than in other floral organs of the flower, and higher in LA2405 than in P86. Phylogenetic analysis of CUL1 sequences and RAPD (random amplified polymorphic DNA) analysis (genome-wide scanning) indicated that flower associated genes may represent a good resource for evaluating evolutionary relationships between tomato species. Taken together the results suggest that comparative biological methods not only represent a platform for detecting evolutionary differences in flowers of different tomato species, but also provide useful data for further dissecting the mechanisms of reproductive behaviors.

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“…Co-transfections were performed as above with equimolar concentrations of DNA, and the total DNA did not exceed 6 g of DNA/10-cm plate. For SCF complex isolation, equimolar amounts of FBXO and Skp1, Cul1, and Rbx1 were transfected as described previously (30). Cells were harvested 48 h after transfection.…”

Section: Cloning and Plasmid Constructsmentioning

confidence: 99%

Diversity in Tissue Expression, Substrate Binding, and SCF Complex Formation for a Lectin Family of Ubiquitin Ligases

Glenn

Nelson

Wen³

et al. 2008

Journal of Biological Chemistry

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Post-translational modification of proteins regulates many cellular processes. Some modifications, including N-linked glycosylation, serve multiple functions. For example, the attachment of N-linked glycans to nascent proteins in the endoplasmic reticulum facilitates proper folding, whereas retention of high mannose glycans on misfolded glycoproteins serves as a signal for retrotranslocation and ubiquitin-mediated proteasomal degradation. Here we examine the substrate specificity of the only family of ubiquitin ligase subunits thought to target glycoproteins through their attached glycans. The five proteins comprising this FBA family (FBXO2, FBXO6, FBXO17, FBXO27, and FBXO44) contain a conserved G domain that mediates substrate binding. Using a variety of complementary approaches, including glycan arrays, we show that each family member has differing specificity for glycosylated substrates. Collectively, the F-box proteins in the FBA family bind high mannose and sulfated glycoproteins, with one FBA protein, FBX044, failing to bind any glycans on the tested arrays. Site-directed mutagenesis of two aromatic amino acids in the G domain demonstrated that the hydrophobic pocket created by these amino acids is necessary for high affinity glycan binding. All FBA proteins co-precipitated components of the canonical SCF complex (Skp1, Cullin1, and Rbx1), yet FBXO2 bound very little Cullin1, suggesting that FBXO2 may exist primarily as a heterodimer with Skp1. Using subunit-specific antibodies, we further demonstrate marked divergence in tissue distribution and developmental expression. These differences in substrate recognition, SCF complex formation, and tissue distribution suggest that FBA proteins play diverse roles in glycoprotein quality control.

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Selective Cochlear Degeneration in Mice Lacking the F-Box Protein, Fbx2, a Glycoprotein-Specific Ubiquitin Ligase Subunit

Abstract: Little is known about the role of protein quality control in the inner ear. We now report selective cochlear degeneration in mice deficient in

Cited by 72 publications

References 41 publications

FBG1 is a promiscuous ubiquitin ligase that sequesters APC2 and causes S-phase arrest

FBG1 is a promiscuous ubiquitin ligase that sequesters APC2 and causes S-phase arrest

Insight into flower diversity inSolanum lycopersicumandSolanum chilenseusing comparative biological approaches

Diversity in Tissue Expression, Substrate Binding, and SCF Complex Formation for a Lectin Family of Ubiquitin Ligases

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