Disease relevance of UBQ6

• We obtained soluble protein for 22 of the 28 uncharacterized UBCs after expression in Escherichia coli and demonstrated that 16 function as ubiquitin E2s [1].
• We have identified a maize ubiquitin (Ubi) fusion gene (UBF9) by screening a maize W22 genomic phage lambda library with a short (16-nucleotide) oligodeoxyribonucleotide probe derived from the sequence for the extension sequence of a yeast UB13 fusion gene [2].
• A transcriptional activator, the Gal4 DNA-binding domain fused to the acidic activation domain of herpes simplex virus VP16 protein, driven by a maize ubiquitin promoter, was introduced in one parental line [3].

High impact information on UBQ6

• These results reveal that a ubiquitin/proteasome pathway negatively regulates ethylene responses by targeting EIN3 for degradation, and pinpoint EIN3 regulation as the key step in the response to ethylene [4].
• We positionally cloned FKF1, which encodes a novel protein with a PAS domain similar to the flavin-binding region of certain photoreceptors, an F box characteristic of proteins that direct ubiquitin-mediated degradation, and six kelch repeats predicted to fold into a beta propeller [5].
• SINAT5 promotes ubiquitin-related degradation of NAC1 to attenuate auxin signals [6].
• Ubiquitin-mediated proteolysis has a central role in this process [6].
• Arabidopsis auxin-resistance gene AXR1 encodes a protein related to ubiquitin-activating enzyme E1 [7].

Biological context of UBQ6

• All ecotypes examined, except Columbia, contain intact open reading frames in the region of the insert, including four ubiquitin codons which Columbia lacks [8].
• Genomic Southern blot analysis showed that ubiquitin sequences comprise a multigene family of approximately 11 members in Arabidopsis [9].
• Ubiquitin DNA sequences were isolated from the higher plant Arabidopsis thaliana L. by screening a lambda-gt11 genomic library with antibodies raised against oat and human ubiquitin [9].
• This gene (UBQ4) encodes a ubiquitin polyprotein with five repeats contiguously linked with no intervening sequences in the coding region and a C-terminal extension of Ser-Phe [9].
• There's the rub: a novel ubiquitin-like modification linked to cell cycle regulation [10].

Anatomical context of UBQ6

• In the eukaryotic cell, depending on the nature of the polyubiquitin chain, the ubiquitin-tagged proteins either see their properties modified or are doomed for degradation by the 26S proteasome [11].
• Northern blot analysis of the Ubiquitin-like gene 5 revealed expression in every tissue tested, with the highest levels of RNA expression in heart, skeletal muscle, kidney, liver, iris, and lymphoblasts [12].

Associations of UBQ6 with chemical compounds

• Proteasome inhibitor studies show that ABI5 stability is regulated by ABA through ubiquitin-related events [13].
• COI1 encodes an F-box protein, which is a subunit of SCF(COI1) E3 ubiquitin ligase, and is required for jasmonate (JA) responses [14].
• Arabidopsis CULLIN4 Forms an E3 Ubiquitin Ligase with RBX1 and the CDD Complex in Mediating Light Control of Development [15].
• The covalent attachment of ubiquitin to lysine residues of targeted proteins is a signal for the recognition and rapid degradation by the proteasome, a large multi-subunit protease [16].
• Our results are consistent with the idea that targets of miRNAs encompass a wide range of transcripts, including those for F-box factors, ubiquitin conjugases, Leucine-rich repeat proteins, and metabolic enzymes, and that regulation by miRNAs might be widespread in the genome [17].

Physical interactions of UBQ6

• Here, we demonstrate that COP10 interacts with ubiquitin-conjugating enzymes (E2s) in vivo, and can enhance their activity in vitro, an activity distinct from previous characterized UEVs such as MMS2 and UEV1 [18].

Regulatory relationships of UBQ6

• To examine the efficacy of this cellular site, oat phytochrome A was also expressed using Arabidopsis chlorophyll a/b-binding protein (CAB) and the Arabidopsis ubiquitin (UBQ1) promoters [19].
• Arabidopsis COP10 forms a complex with DDB1 and DET1 in vivo and enhances the activity of ubiquitin conjugating enzymes [18].
• Here we show that CIP8 promotes ubiquitin attachment to HY5 in E2-dependent fashion in vitro [20].
• Likewise, the fact that ATL2 and other members of the ATL family are activated in eca mutants links the induction of this putative class of ubiquitin ligases to plant defense signaling pathways [21].
• SIR1 is predicted to encode a protein composed of a ubiquitin-activating enzyme E1-like domain and a Rhodanese-like domain homologous to that of prolyl isomerase [22].

Other interactions of UBQ6

• Ubiquitin extension protein genes encode the smallest transcript size class of ubiquitin mRNAs in Arabidopsis [23].
• The AXR1 (auxin-resistant) protein, which has features of the ubiquitin-activating enzyme E1, is required for normal response to the plant hormone auxin in Arabidopsis thaliana [24].
• The ubiquitin-related protein RUB1 and auxin response in Arabidopsis [24].
• Among them, COP1 and the COP9 signalosome have been hypothesized to fulfill the roles as an ubiquitin ligase (E3) and an essential E3 modulator [25].
• COP1 functions as an E3 ubiquitin ligase, targeting select proteins for proteasomal degradation in plants as well as in mammals [26].

Analytical, diagnostic and therapeutic context of UBQ6

• The E3 ubiquitin ligase BIG BROTHER controls arabidopsis organ size in a dosage-dependent manner [27].
• The specific binding of CaM to CaM binding domain was confirmed by site-directed mutagenesis, a gel mobility shift assay, split ubiquitin assay, and a competition assay using a Ca2+/CaM-dependent enzyme [28].
• Rat cDNAs for a 52-amino-acid ribosomal protein (CEP52) that is typically formed as a ubiquitin fusion protein, were cloned following reverse transcription and PCR amplification [29].

References