Disease relevance of SGT1

• We have recently isolated a rat cDNA encoding a novel cellular protein able to interact with the major nonstructural protein NS1 of parvovirus H-1 and have termed this protein SGT, for small glutamine-rich tetratricopeptide repeat (TPR)-containing protein [1].

High impact information on SGT1

• We have identified SGT1 as a dosage suppressor of skp1-4, a mutation causing defects in yeast kinetochore function [2].
• Sgt1p physically associates with Skp1p in vivo and in vitro [2].
• Sgt1p is required for assembling the yeast kinetochore complex, CBF3, via activation of Ctf13p [2].
• RAR1 and its interacting partner SGT1 play a central role in plant disease resistance triggered by a number of resistance (R) proteins [3].
• Our findings show that silencing SGT1 affects diverse types of disease resistance in plants and support the idea that R protein-mediated and nonhost resistance may involve similar mechanisms [4].

Biological context of SGT1

• Genetic studies of budding yeast suggest a role for SGT1 in signal transduction, cell cycle advance, and chromosome segregation [5].
• The RAR1 interactor SGT1, an essential component of R gene-triggered disease resistance [6].
• Here, we show that RAR1 interacts with plant orthologs of the yeast protein SGT1, an essential regulator in the cell cycle [6].
• Defense signaling of the Bs4-governed reaction was studied in Nicotiana benthamiana by virus-induced gene silencing and showed that Bs4-mediated resistance is EDS1- and SGT1-dependent [7].
• The Sgt2 gene was identified by deduced protein sequence homology to the previously identified Sgt1 gene [8].

Anatomical context of SGT1

• We report that RNA interference-mediated depletion of Sgt1 from HeLa cells causes dramatic alterations of the mitotic spindle and problems in chromosome alignment [9].
• Then, by western blot, we checked the localization of Sgt1 in some areas of the rat brain such as cortex, cerebellum and hippocampus and we found that cerebellum and cortex contain highest amounts of this protein [10].
• The expression and function of Sgt1 protein in eukaryotic cells [10].
• Using immunohistochemistry we found that the Sgt1 protein is present in both neurons and glial cells [10].
• Using northern and western blots we found that the Sgt1 protein is expressed in various tissues and that brain, skeletal muscles and spleen contain high levels of this protein and its mRNA [10].

Associations of SGT1 with chemical compounds

• SGT1 is an allele-specific suppressor of cdc35-1, a thermosensitive mutation in the leucine-rich repeat domain of the adenylyl cyclase Cyrlp/Cdc35p [11].
• The S. cerevisiae and human SGT1 genes both suppress git7-93 but not git7-235 for glucose repression of fbp1 transcription and benomyl sensitivity [12].
• Sgt1p contributes to cyclic AMP pathway activity and physically interacts with the adenylyl cyclase Cyr1p/Cdc35p in budding yeast [11].

Physical interactions of SGT1

• We have found that Sgt1 interacts with Hsp90 in yeast [13].
• Analyses of the dimerization of Sgt1 deletion proteins showed that the Skp1-binding domain (amino acids 1-211) contains the Sgt1 homodimerization domain [14].

Other interactions of SGT1

• Sgt1 associates with Hsp90: an initial step of assembly of the core kinetochore complex [13].
• Ubiquitin ligase-associated protein SGT1 is required for host and nonhost disease resistance in plants [4].

References