Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae
Abstract Background Myo-Inositol Phosphate Synthase (MIP) catalyzes the conversion of glucose 6- phosphate into inositol phosphate, an essential nutrient and cell signaling molecule. Data obtained, first in bovine brain and later in plants, established MIP expression in organelles and in extracellul...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2021-07-01
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| Series: | Microbial Cell Factories |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s12934-021-01610-6 |
| _version_ | 1818921962603282432 |
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| author | Erika Steele Hana D. Alebous Macy Vickers Mary E. Harris Margaret D. Johnson |
| author_facet | Erika Steele Hana D. Alebous Macy Vickers Mary E. Harris Margaret D. Johnson |
| author_sort | Erika Steele |
| collection | DOAJ |
| description | Abstract Background Myo-Inositol Phosphate Synthase (MIP) catalyzes the conversion of glucose 6- phosphate into inositol phosphate, an essential nutrient and cell signaling molecule. Data obtained, first in bovine brain and later in plants, established MIP expression in organelles and in extracellular environments. A physiological role for secreted MIP has remained elusive since its first detection in intercellular space. To provide further insight into the role of MIP in intercellular milieus, we tested the hypothesis that MIP may function as a growth factor, synthesizing inositol phosphate in intercellular locations requiring, but lacking ability to produce or transport adequate quantities of the cell–cell communicator. This idea was experimentally challenged, utilizing a Saccharomyces cerevisiae inositol auxotroph with no MIP enzyme, permeable membranes with a 0.4 µm pore size, and cellular supernatants as external sources of inositol isolated from S. cerevisiae cells containing either wild-type enzyme (Wt-MIP), no MIP enzyme, auxotroph (Aux), or a green fluorescent protein (GFP) tagged reporter enzyme (MIP- GFP) in co- culturing experiments. Results Resulting cell densities and microscopic studies with corroborating biochemical and molecular analyses, documented sustained growth of Aux cells in cellular supernatant, concomitant with the uptakeof MIP, detected as MIP-GFP reporter enzyme. These findings revealed previously unknown functions, suggesting that the enzyme can: (1) move into and out of intercellular space, (2) traverse cell walls, and (3) act as a growth factor to promote cellular proliferation of an inositol requiring cell. Conclusions Co-culturing experiments, designed to test a probable function for MIP secreted in extracellular vesicles, uncovered previously unknown functions for the enzyme and advanced current knowledge concerning spatial control of inositol phosphate biosynthesis. Most importantly, resulting data identified an extracellular vesicle (a non-viral vector) that is capable of synthesizing and transporting inositol phosphate, a biological activity that can be used to enhance specificity of current inositol phosphate therapeutics. |
| first_indexed | 2024-12-20T01:45:59Z |
| format | Article |
| id | doaj.art-71a2ea814a514d28862a6a5a9730ecf9 |
| institution | Directory Open Access Journal |
| issn | 1475-2859 |
| language | English |
| last_indexed | 2024-12-20T01:45:59Z |
| publishDate | 2021-07-01 |
| publisher | BMC |
| record_format | Article |
| series | Microbial Cell Factories |
| spelling | doaj.art-71a2ea814a514d28862a6a5a9730ecf92022-12-21T19:57:45ZengBMCMicrobial Cell Factories1475-28592021-07-0120111310.1186/s12934-021-01610-6Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiaeErika Steele0Hana D. Alebous1Macy Vickers2Mary E. Harris3Margaret D. Johnson4The University of Alabama, The Institute of Social Science ResearchDepartment of Biological Sciences, School of Science, The University of JordanDepartment of Biological Sciences, The University of AlabamaDepartment of Biological Sciences, The University of AlabamaDepartment of Biological Sciences, The University of AlabamaAbstract Background Myo-Inositol Phosphate Synthase (MIP) catalyzes the conversion of glucose 6- phosphate into inositol phosphate, an essential nutrient and cell signaling molecule. Data obtained, first in bovine brain and later in plants, established MIP expression in organelles and in extracellular environments. A physiological role for secreted MIP has remained elusive since its first detection in intercellular space. To provide further insight into the role of MIP in intercellular milieus, we tested the hypothesis that MIP may function as a growth factor, synthesizing inositol phosphate in intercellular locations requiring, but lacking ability to produce or transport adequate quantities of the cell–cell communicator. This idea was experimentally challenged, utilizing a Saccharomyces cerevisiae inositol auxotroph with no MIP enzyme, permeable membranes with a 0.4 µm pore size, and cellular supernatants as external sources of inositol isolated from S. cerevisiae cells containing either wild-type enzyme (Wt-MIP), no MIP enzyme, auxotroph (Aux), or a green fluorescent protein (GFP) tagged reporter enzyme (MIP- GFP) in co- culturing experiments. Results Resulting cell densities and microscopic studies with corroborating biochemical and molecular analyses, documented sustained growth of Aux cells in cellular supernatant, concomitant with the uptakeof MIP, detected as MIP-GFP reporter enzyme. These findings revealed previously unknown functions, suggesting that the enzyme can: (1) move into and out of intercellular space, (2) traverse cell walls, and (3) act as a growth factor to promote cellular proliferation of an inositol requiring cell. Conclusions Co-culturing experiments, designed to test a probable function for MIP secreted in extracellular vesicles, uncovered previously unknown functions for the enzyme and advanced current knowledge concerning spatial control of inositol phosphate biosynthesis. Most importantly, resulting data identified an extracellular vesicle (a non-viral vector) that is capable of synthesizing and transporting inositol phosphate, a biological activity that can be used to enhance specificity of current inositol phosphate therapeutics.https://doi.org/10.1186/s12934-021-01610-6Inositol auxotrophSaccharomyces cerevisiaeMyo-inositol Phosphate Synthase (MIP)Protein secretionCellular supernatantExtracellular vesicle |
| spellingShingle | Erika Steele Hana D. Alebous Macy Vickers Mary E. Harris Margaret D. Johnson Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae Microbial Cell Factories Inositol auxotroph Saccharomyces cerevisiae Myo-inositol Phosphate Synthase (MIP) Protein secretion Cellular supernatant Extracellular vesicle |
| title | Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae |
| title_full | Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae |
| title_fullStr | Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae |
| title_full_unstemmed | Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae |
| title_short | Co-culturing experiments reveal the uptake of myo-inositol phosphate synthase (EC 5.5.1.4) in an inositol auxotroph of Saccharomyces cerevisiae |
| title_sort | co culturing experiments reveal the uptake of myo inositol phosphate synthase ec 5 5 1 4 in an inositol auxotroph of saccharomyces cerevisiae |
| topic | Inositol auxotroph Saccharomyces cerevisiae Myo-inositol Phosphate Synthase (MIP) Protein secretion Cellular supernatant Extracellular vesicle |
| url | https://doi.org/10.1186/s12934-021-01610-6 |
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