Regulatory Role of
            <i>SGT1</i>
            in Early
            <i>R</i>
            Gene-Mediated Plant Defenses

Austin, Mark; Muskett, Paul; Kahn, Katherine; Feys, Bart J.; Jones, Jonathan D. G.; Parker, Jane E.

doi:10.1126/science.1067747

Cited by 385 publications

(280 citation statements)

References 22 publications

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“…The plant SGT1 (Suppressor of G2 allele of skp1) gene was first isolated independently by two laboratories; one in the searching for interacting proteins for the key signaling component of multiple R-gene-mediated resistance, RAR1 [12], and the other in the screening for the genes essential for R gene RPP5-mediated disease resistance, respectively [92,93]. Studies from several groups indicated that SGT1 is required by a diverse range of R genes from different plant species in response to a variety of pathogens [61,[92][93][94][95].…”

Section: U-box-type E3 Ligases Are Newly Identified Members Of the Ubmentioning

confidence: 99%

“…Studies from several groups indicated that SGT1 is required by a diverse range of R genes from different plant species in response to a variety of pathogens [61,[92][93][94][95]. In yeast, SGT1 is a key regulatory protein in centromere function and cell cycle transition and is associated with SKP1 to regulate the activity of the SCF E3 ligase complex [96].…”

Section: U-box-type E3 Ligases Are Newly Identified Members Of the Ubmentioning

confidence: 99%

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Ubiquitination-mediated protein degradation and modification: an emerging theme in plant-microbe interactions

et al. 2006

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Post-translational modification is central to protein stability and to the modulation of protein activity. Various types of protein modification, such as phosphorylation, methylation, acetylation, myristoylation, glycosylation, and ubiquitination, have been reported. Among them, ubiquitination distinguishes itself from others in that most of the ubiquitinated proteins are targeted to the 26S proteasome for degradation. The ubiquitin/26S proteasome system constitutes the major protein degradation pathway in the cell. In recent years, the importance of the ubiquitination machinery in the control of numerous eukaryotic cellular functions has been increasingly appreciated. Increasing number of E3 ubiquitin ligases and their substrates, including a variety of essential cellular regulators have been identified. Studies in the past several years have revealed that the ubiquitination system is important for a broad range of plant developmental processes and responses to abiotic and biotic stresses. This review discusses recent advances in the functional analysis of ubiquitination-associated proteins from plants and pathogens that play important roles in plant-microbe interactions.

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Section: U-box-type E3 Ligases Are Newly Identified Members Of the Ubmentioning

confidence: 99%

Section: U-box-type E3 Ligases Are Newly Identified Members Of the Ubmentioning

confidence: 99%

Ubiquitination-mediated protein degradation and modification: an emerging theme in plant-microbe interactions

et al. 2006

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“…Arabidopsis contains two SGT1 genes (Austin et al, 2002). Mutations in SGT1b compromise resistance mediated by a specific subset of NB-LRR proteins that only partially overlaps with those affected by rar1 mutations.…”

Section: Other Components Of the Plant Alarm Systemmentioning

confidence: 99%

Guarding the Goods. New Insights into the Central Alarm System of Plants

Innes

2004

Plant Physiology

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“…It remains to be shown whether RAR1 and/or SGT1 associate together with HSP90 and R proteins in a single complex and/or simultaneously co-regulate other complexes required for potential 'downstream' signalling events, such as ubiquitination-dependent processes [16][17][18]. An indication that the former might be true is the observation that RPM1 steady-state levels are greatly decreased or undetectable in non-challenged rar1 or hsp90.2 mutant backgrounds [7,19].…”

mentioning

confidence: 99%

Plant Immunity: The Origami of Receptor Activation

Schulze-Lefert¹

2004

Current Biology

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Mutations in plant cytosolicOne of the HSP90.2 substitutions is equivalent to that creating a mutant form of yeast HSP90 that lacks the ATPase activity required for client turnover, yet retains the ability to dimerize. Paradoxically, an insertion allele of AtHSP90.2, presumably a null mutation, had no discernible effect on RPM1 function. Furthermore, the Athsp90.2 mutant alleles with ATP binding site substitutions revealed a baroque genetic condition known as 'non-allelic non-complementation'. In such cases, F 1 heterozygous products of a cross between plants bearing two unlinked recessive mutations are phenotypically similar to either homozygous single mutant. In this particular case, F 1 plants containing wild-type and mutant alleles of both RPM1 and HSP90.2 were susceptible to P. syringae expressing avrRpm1.Non-allelic non-complementation provides clear evidence for dosage-sensitivity, and also suggests close physical associations -either direct physical interaction between RPM1 and HSP90.2 or an association in the same complex. Indeed, co-immunoprecipitation of RPM1 and HSP90 from plant extracts supported the conclusion that the proteins associate in vivo, although it remains to be shown whether the interaction is really direct and preferentially involves HSP90.2 and/or any of the other three closely related cytosolic HSP90 isoforms. One way of rationalizing the findings invokes functional redundancy in the HSP90 family, which could prevent inactivation of RPM1 in the Athsp90.2 null mutant, whereas mutations of the HSP90.2 ATPase domain might prohibit functional redundancy by causing persistent, but non-productive, client binding.In this scenario, non-productive binding might force incompletely folded RPM1 to enter a default degradation pathway. Hubert et al.[7] thus concluded that HSP90.2 has a role in folding RPM1 into a stable conformation or a signalling competent RPM1-containing complex. Preliminary evidence for the latter was obtained by co-immunoprecipitation experiments involving the Arabidopsis RIN4 protein. RIN4 is another component essential for RPM1 function and is known to interact directly with both RPM1 and the cognate Pseudomonas effector AvrRpm1 on the cytoplasmic face of plant plasma membranes [2]. In co-immunoprecipitation experiments, RIN4 did not appear to interact with HSP90, suggesting the existence of at least two pools of RPM1. This may also indicate that HSP90 acts transiently in the assembly of an RPM1-containing

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Regulatory Role of SGT1 in Early R Gene-Mediated Plant Defenses

Cited by 385 publications

References 22 publications

Ubiquitination-mediated protein degradation and modification: an emerging theme in plant-microbe interactions

Ubiquitination-mediated protein degradation and modification: an emerging theme in plant-microbe interactions

Guarding the Goods. New Insights into the Central Alarm System of Plants

Plant Immunity: The Origami of Receptor Activation

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