ESCRT components regulate the expression of the ER/Golgi calcium pump gene PMR1 through the Rim101/Nrg1 pathway in budding yeast

Abstract

The endosomal sorting complex required for transport (ESCRT) complexes function to form multivesicular bodies for sorting of proteins destined for the yeast vacuole or the mammalian lysosome. ESCRT components are well conserved in eukaryotes, and their mutations cause neurodegenerative diseases and other cellular pathologies in humans. PMR1 is the orthologous gene of two human genes for calcium pumps secretory pathway Ca(2+)-ATPase (SPCA1, ATP2C1) and sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA, ATP2A2), which are mutated in Hailey-Hailey and Darier genetic diseases, respectively. Here we show that deletion mutation of ESCRT components Snf7, Snf8, Stp22, Vps20, Vps25, Vps28, or Vps36 activates the calcium/calcineurin signaling in yeast cells, but surprisingly leads to a nearly 50% reduction in expression of the ER/Golgi calcium pump gene PMR1 independent of calcium stress. These ESCRT mutants are known to have a defect in Rim101 activation. Ectopic expression of a constitutively active form of Rim101 or further deletion of NRG1 in these mutants partially suppresses their calcium hypersensitivity. Deletion of NRG1 also completely rescues the expression of PMR1 in these mutants to the level of the wild type. Promoter mutagenesis, gel electrophoretic mobility shift assay, and chromatin immunoprecipitation analysis demonstrate that Nrg1 binds to two motifs in the PMR1 promoter. In addition, expression of PMR1 under the control of its promoters with mutated Nrg1-binding motifs suppresses the calcium hypersensitivity of these ESCRT mutants. Collectively, these data have uncovered a function of ESCRT components in regulating PMR1 expression through the Nrg1/Rim101 pathway. Our findings provide important clues for understanding human diseases related to calcium homeostasis.

Components of the Calcium-Calcineurin Signaling Pathway in Fungal Cells and Their Potential as Antifungal Targets

“…Subsequently, the intracellular Ca 2ϩ level is reduced to the basal level due to the uptake of Ca 2ϩ by organelles and the inhibition of Ca 2ϩ release from the vacuole. While this set of calcineurin targets generally seems to be coordinately regulated, the authors of another report (80) demonstrate that a deletion mutation of any of the components SNF7, SNF8, STP22, VPS20, VPS25, VPS28, and VPS36 of the endosomal sorting complex required for transport (ESCRT) complex activates Ca 2ϩ /CN signaling in yeast cells but, surprisingly, reduces the expression of the ER/Golgi calcium pump gene PMR1 by nearly half, independent of calcium stress. Although this finding seems to contradict the well-known fact that Ca2 ϩ /CN signaling positively regulates Pmr1, it is consistent with the important role of PMR1, together with PMC1, in preventing the lethal activation of calcineurin under standard (low-Ca 2ϩ ) conditions (81).…”

Endosomal sorting complexes required for ESCRTing cells toward death during neurogenesis, neurodevelopment and neurodegeneration

“…ESCRT components Snf7, Snf8, Stp22, Vps20, Vps25, Vps28 and Vps36 regulate the expression of the ER/Golgi calcium pump gene in yeast PMR1 , the ortholog of 2 human genes for calcium pumps—the secretory pathway Ca 2+ ‐ATPase (SPCA1, ATP2C1) and the sarco/ER Ca 2+ ‐ATPase (SERCA, ATP2A2) . It is reported that mutations in these ESCRT components can lead to almost 50% reduction in the expression of the ER/Golgi calcium pump gene PMR1 .…”

“…ESCRT components Snf7, Snf8, Stp22, Vps20, Vps25, Vps28 and Vps36 regulate the expression of the ER/Golgi calcium pump gene in yeast PMR1 , the ortholog of 2 human genes for calcium pumps—the secretory pathway Ca 2+ ‐ATPase (SPCA1, ATP2C1) and the sarco/ER Ca 2+ ‐ATPase (SERCA, ATP2A2) . It is reported that mutations in these ESCRT components can lead to almost 50% reduction in the expression of the ER/Golgi calcium pump gene PMR1 . Parallel evidences exist to highlight the importance of calcium pumps like the plasma membrane calcium ATPases (PMCAs) in the survival of spinal cord (SC) neurons; a reduction in PMCA2 expression induces death of SC neurons .…”

“…Furthermore, the ESCRT component, Snf8, is shown to interact with one of the canonical transient receptor potential (TRPC) family members, TRPC6 involved in receptor‐mediated calcium signaling in diverse cells and tissues. Enhanced activity of TRPC6 is lethal for cells and it exerts its effects through ESCRT accessory proteins such as Alix and ALG‐2 …”

Yeast as a model system to study metabolic impact of selenium compounds

“…Later studies showed its implication in processes such as sporulation and invasive growth, protection against Na + and Li + toxicity, cell wall assembly, protection against weak organic acids and regulation of calcium homeostasis 109110111112. A recent study 113 has extended the range of cell processes regulated by Rim101 to vacuolar functions.…”