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| Title | Regulatory mechanisms of PP2A complex assembly driven by physicochemical differences in A-subunit isoforms. |
|---|---|
| Journal, issue, pages | Structure, Vol. 33, Issue 10, Page 1688-11699.e5, Year 2025 |
| Publish date | Oct 2, 2025 |
Authors | Alexander Day / Wei Huang / Daniel Leonard / Caitlin M O'Connor / Goutham Narla / Derek J Taylor / ![]() |
| PubMed Abstract | Protein phosphatase 2A (PP2A) is crucial for regulating cellular pathways, with its holoenzyme assembly affecting enzyme function and substrate selection. The PP2A holoenzyme comprises scaffold A-, ...Protein phosphatase 2A (PP2A) is crucial for regulating cellular pathways, with its holoenzyme assembly affecting enzyme function and substrate selection. The PP2A holoenzyme comprises scaffold A-, regulatory B-, and catalytic C-subunits, each with various isoforms. Here, we examine structural and biochemical characteristics of the A-subunit isoforms (Aα and Aβ) and identify different biophysical properties that may promote distinct PP2A functions. Our molecular dynamics simulations and cryo-EM analyses define structural differences in the isoforms that reside primarily at the N-terminus of the A-subunit where it interfaces with regulatory B-subunits. Kinetic analyses show Aβ has a lower binding affinity in complexes with B56 subunits and exhibits unique aggregative properties as a monomeric protein. These findings suggest that the different physicochemical properties between A-subunit isoforms are key to PP2A holoenzyme assembly and function. We predict that the Aβ serves as a reservoir, ensuring that serine-threonine phosphatase activity is maintained during high regulatory demand. |
External links | Structure / PubMed:40712571 / PubMed Central |
| Methods | EM (single particle) |
| Resolution | 3.2 - 3.4 Å |
| Structure data | EMDB-48224, PDB-9mf5: EMDB-48300, PDB-9mip: |
| Chemicals | ![]() ChemComp-MN: |
| Source |
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Keywords | SIGNALING PROTEIN / HYDROLASE / Phosphatase / Complex / Holoenzyme / Heterotrimer / PP2A |
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homo sapiens (human)
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