SGT1 is a protein found in yeasts, plants, and mammals in both the nucleus and the cytosol. It functions in several biological processes through interaction with different multi-protein complexes. A large body of evidence also suggests that the protein plays a role in regulating pathogen resistance in plants. Various genetic studies have identified SGT1 as a crucial component for pathogen resistance in plants through regulation of expression and activities of some R proteins
Although there is a significant genetic crossover between plants and mammals, very little is known about this common human-plant regulatory pathway. Ulevitch speculated that certain protein regulatory structures might exist in both plants and humans simply because they do the same thing in much the same way.
"In reality," he said, "there are only so many ways to accomplish related biological responses."
The study also showed that a heat shock protein, HSP90, helped stabilize Nod1.
"Inhibiting HSP90 resulted in a significant reduction of Nod1 protein levels," Ulevitch said. "That clearly suggests that this protein plays a key role in stabilizing Nod1 and protecting it from degradation. In contrast, turning off SGT1 did not alter levels of Nod1."
In an earlier study, Ulevitch’s laboratory reported that Nod1 also interacted with the COP9 complex, a multiprotein complex that is known to play a role in a number of development pathways in plants and that has a mammalian counterpart. This interaction, Ulevitch noted, provides a second link between Nod1 and plant R protein pathways.
"The association of Nod1 with SGT1 and the COP9 complex suggests that one possible ro
Source:Scripps Research Institute