AlphaFold-Multimer (v3) model of a complex of Protein Phosphatase 2A catalytic subunit (PP2A/C), PP2A scaffold subunit (PP2A/A), the B55alpha substrate binding subunit, and FAM122A, a PP2A inhibitor protein.

<p>AlphaFold-Multimer (v3) model structure of a complex of Protein Phosphatase 2A catalytic subunit (PP2A/C), PP2A scaffold subunit (PP2A/A), the B55alpha substrate binding subunit, and FAM122A, a PP2A inhibitor protein. The protein sequences were obtained from UniProt:</p> <p>P67775 &middot; PP2AA_HUMAN</p> <p>P30153 &middot; 2AAA_HUMAN</p> <p>P63151 &middot; 2ABA_HUMAN</p> <p>Q96E09 &middot; PBIR1_HUMAN</p> <p>Coordinates are in mmCIF format. A PyMOL session file is included.</p> <p>Modeling was performed with AlphaFold-Multimer v3, downloaded from DeepMind&#39;s github. Structure prediction was performed without templates. The model was relaxed with Amber.</p> <p>FAM122A binds using a short linear motif (SLIM) (residues 84-89) first identified in RBL1 (p107) (Fowle et al., eLife, <a href="https://doi.org/10.7554/eLife.63181">https://doi.org/10.7554/eLife.63181</a> in the form of a short alpha helix (residues 84-92). This is followed by a long alpha helix (residues 96-122) which blocks access to the active site of the catalytic subunit. There are further contacts of FAM122A (residues 150-170) with one of the beta sheets of the B55alpha beta propeller domain. FAM122A regulates PP2A activity during the cell cycle.</p> <p>&nbsp;</p>