Disease relevance of SPI1

• This protein showed 52% identity to human TC4 and 50% identity to yeast Spi1 proteins, suggesting that it is closely related to the Ran proteins, and it was therefore designated gRan. gRan produced from recombinant Escherichia coli exhibited GTP binding activity by an overlay assay [1].
• In this study, we have utilized the yeast two-hybrid assay to identify protein-protein interactions between effector and chaperone proteins encoded within Salmonella pathogenicity island 1 (SPI-1) [2].

High impact information on SPI1

• Unlike wild-type cells, cells expressing Ctk1(T338A) delayed growth at early stationary phase, did not show the increase in Ser2 phosphorylation that normally accompanies the transition from rapid growth to stationary phase, and had compromised transcriptional activation of two stationary-phase genes, CTT1 and SPI1 [3].
• We found that overexpression of Spi1p rescues the S. pombe Delta mog1 cells from death [4].
• The SPI1 Gene, Encoding a Glycosylphosphatidylinositol-Anchored Cell Wall Protein, Plays a Prominent Role in the Development of Yeast Resistance to Lipophilic Weak-Acid Food Preservatives [5].
• Activation of SPI1 transcription upon acetic acid stress also requires Haa1p, whereas this recently described transcription factor has a negligible role in the adaptive response to benzoic acid [5].
• The expression of SPI1 was found to play a prominent role in the development of yeast resistance to 1,3-beta-glucanase in benzoic acid-stressed cells, while its involvement in acetic acid-induced resistance to the cell wall-lytic enzyme is slighter [5].

Biological context of SPI1

• The amino acid sequence of the obtained plant Ran-homologue, designated Vfa-ran, is 74% and 76% identical to Ran and Spi1, respectively [6].
• However, as in Ran/Spi1 the C-terminus of Vfa-ran is very acidic and lacks the Cys motif for isoprenylation [6].
• The Ran/Spi1 proteins interact with a protein bound to DNA (RCC1) and are thought to function in the regulation of the cell cycle [6].

Associations of SPI1 with chemical compounds

• SPI1 mRNA levels were reduced to values slightly above those in unstressed cells when the adapted population started duplication in the presence of 2,4-D [7].
• Maximal protection exerted by Spi1p against equivalent concentrations of the various weak acids tested was registered for the more lipophilic acids (octanoic acid, followed by benzoic acid) and was minimal for acetic acid [5].

Other interactions of SPI1

• Significantly, yeast adaptation to 2,4-D involves the rapid and transient Msn2p- and Msn4p-mediated activation (fivefold) of SPI1 transcription [7].

References