PDZ-directed substrate recruitment is the primary determinant of specific 4E-BP1 dephosphorylation by PP1-Neurabin
Phosphoprotein phosphatase 1 (PP1) relies on association with PP1-interacting proteins (PIPs) to generate substrate-specific PIP/PP1 holoenzymes, but the lack of well-defined substrates has hindered elucidation of the mechanisms involved. We previously demonstrated that the Phactr1 PIP confers seque...
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eLife Sciences Publications Ltd
2025-06-01
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| Online Access: | https://elifesciences.org/articles/103403 |
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| author | Roman O Fedoryshchak Karim El-Bouri Dhira Joshi Stephane Mouilleron Richard Treisman |
| author_facet | Roman O Fedoryshchak Karim El-Bouri Dhira Joshi Stephane Mouilleron Richard Treisman |
| author_sort | Roman O Fedoryshchak |
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| description | Phosphoprotein phosphatase 1 (PP1) relies on association with PP1-interacting proteins (PIPs) to generate substrate-specific PIP/PP1 holoenzymes, but the lack of well-defined substrates has hindered elucidation of the mechanisms involved. We previously demonstrated that the Phactr1 PIP confers sequence specificity on the Phactr1/PP1 holoenzyme by remodelling the PP1 hydrophobic substrate groove. Phactr1 defines a group of ‘RVxF-ΦΦ-R-W’ PIPs that all interact with PP1 in a similar fashion. Here, we use a PP1-PIP fusion approach to address sequence specificity and identify substrates of the RVxF-ΦΦ-R-W family PIPs. We show that the four Phactr proteins confer identical sequence specificities on their holoenzymes. We identify the 4E-BP and p70 S6K translational regulators as substrates for the Neurabin/Spinophilin PIPs, implicated in neuronal plasticity, pointing to a role for their holoenzymes in mTORC1-dependent translational control. Biochemical and structural experiments show that in contrast to the Phactrs, substrate recruitment and catalytic efficiency of the PP1-Neurabin and PP1-Spinophilin fusions is primarily determined by substrate interaction with the PDZ domain adjoining their RVxF-ΦΦ-R-W motifs, rather than by recognition of the remodelled PP1 hydrophobic groove. Thus, even PIPs that interact with PP1 in a similar manner use different mechanisms to ensure substrate selectivity. |
| format | Article |
| id | doaj-art-c998da46fa954e82aaa971c62e656b42 |
| institution | DOAJ |
| issn | 2050-084X |
| language | English |
| publishDate | 2025-06-01 |
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| spelling | doaj-art-c998da46fa954e82aaa971c62e656b422025-08-20T03:23:08ZengeLife Sciences Publications LtdeLife2050-084X2025-06-011310.7554/eLife.103403PDZ-directed substrate recruitment is the primary determinant of specific 4E-BP1 dephosphorylation by PP1-NeurabinRoman O Fedoryshchak0https://orcid.org/0000-0003-1865-8372Karim El-Bouri1https://orcid.org/0000-0002-4542-0856Dhira Joshi2https://orcid.org/0000-0001-8660-2528Stephane Mouilleron3https://orcid.org/0000-0001-7977-6298Richard Treisman4https://orcid.org/0000-0002-9658-0067Signalling and Transcription Laboratory, Francis Crick Institute, London, United KingdomStructural Biology STP, Francis Crick Institute, London, United KingdomChemical Biology STP, Francis Crick Institute, London, United KingdomStructural Biology STP, Francis Crick Institute, London, United KingdomSignalling and Transcription Laboratory, Francis Crick Institute, London, United KingdomPhosphoprotein phosphatase 1 (PP1) relies on association with PP1-interacting proteins (PIPs) to generate substrate-specific PIP/PP1 holoenzymes, but the lack of well-defined substrates has hindered elucidation of the mechanisms involved. We previously demonstrated that the Phactr1 PIP confers sequence specificity on the Phactr1/PP1 holoenzyme by remodelling the PP1 hydrophobic substrate groove. Phactr1 defines a group of ‘RVxF-ΦΦ-R-W’ PIPs that all interact with PP1 in a similar fashion. Here, we use a PP1-PIP fusion approach to address sequence specificity and identify substrates of the RVxF-ΦΦ-R-W family PIPs. We show that the four Phactr proteins confer identical sequence specificities on their holoenzymes. We identify the 4E-BP and p70 S6K translational regulators as substrates for the Neurabin/Spinophilin PIPs, implicated in neuronal plasticity, pointing to a role for their holoenzymes in mTORC1-dependent translational control. Biochemical and structural experiments show that in contrast to the Phactrs, substrate recruitment and catalytic efficiency of the PP1-Neurabin and PP1-Spinophilin fusions is primarily determined by substrate interaction with the PDZ domain adjoining their RVxF-ΦΦ-R-W motifs, rather than by recognition of the remodelled PP1 hydrophobic groove. Thus, even PIPs that interact with PP1 in a similar manner use different mechanisms to ensure substrate selectivity.https://elifesciences.org/articles/103403phosphataseNeurabin4E-BP1PhactrPIPmTORC1 |
| spellingShingle | Roman O Fedoryshchak Karim El-Bouri Dhira Joshi Stephane Mouilleron Richard Treisman PDZ-directed substrate recruitment is the primary determinant of specific 4E-BP1 dephosphorylation by PP1-Neurabin eLife phosphatase Neurabin 4E-BP1 Phactr PIP mTORC1 |
| title | PDZ-directed substrate recruitment is the primary determinant of specific 4E-BP1 dephosphorylation by PP1-Neurabin |
| title_full | PDZ-directed substrate recruitment is the primary determinant of specific 4E-BP1 dephosphorylation by PP1-Neurabin |
| title_fullStr | PDZ-directed substrate recruitment is the primary determinant of specific 4E-BP1 dephosphorylation by PP1-Neurabin |
| title_full_unstemmed | PDZ-directed substrate recruitment is the primary determinant of specific 4E-BP1 dephosphorylation by PP1-Neurabin |
| title_short | PDZ-directed substrate recruitment is the primary determinant of specific 4E-BP1 dephosphorylation by PP1-Neurabin |
| title_sort | pdz directed substrate recruitment is the primary determinant of specific 4e bp1 dephosphorylation by pp1 neurabin |
| topic | phosphatase Neurabin 4E-BP1 Phactr PIP mTORC1 |
| url | https://elifesciences.org/articles/103403 |
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