{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nPHLPP1 is a serine/threonine protein phosphatase that serves as a key “brake” in growth factor–induced signaling by directly dephosphorylating the hydrophobic motifs of AGC kinases. In doing so, PHLPP1 terminates Akt signaling—in an isoform‐selective manner—and similarly targets protein kinase C, thereby tightly controlling kinase activity and the life‐cycle of these signaling proteins. This direct dephosphorylation mechanism is critical for maintaining appropriate cellular proliferation and survival signals."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "3"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its role in signal termination, PHLPP1 functions as a potent tumor suppressor. Its activity has been shown to curb oncogenic signaling in prostate, colon, and pancreatic cancers by dampening Akt activation, thereby inhibiting cell-cycle progression and proliferation. Moreover, PHLPP1 promotes apoptosis via dephosphorylation and subsequent activation of pro-apoptotic effectors such as Mst1. Loss of PHLPP1 expression—whether occurring through genetic deletion, enhanced proteolysis mediated by E3 ubiquitin ligases, or by the action of regulatory RNAs such as microRNA-141, MEG3, and Xist—leads to aberrant Akt hyperactivation and contributes to tumor progression."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "4", "end_ref": "12"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nThe cellular levels and activity of PHLPP1 are exquisitely regulated by multiple post‐translational and translational mechanisms. Its degradation is promoted by phosphorylation‐dependent recruitment of E3 ubiquitin ligases such as beta-TrCP, whereas stabilization is conferred by deubiquitinases—including USP46 as well as the WDR48–USP12 complex—and by membrane recruitment via the scaffold protein Scribble, which enhances its ability to curb Akt signaling. Moreover, mTOR-dependent translational control further adjusts PHLPP1 protein levels, influencing cellular responses such as insulin sensitivity and protein synthesis (via substrates like S6K1). These regulatory mechanisms underscore the central role of PHLPP1 in maintaining cellular homeostasis and its impact on disease processes."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "13", "end_ref": "22"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "John Brognard, Emma Sierecki, Tianyan Gao, et al. "}, {"type": "b", "children": [{"type": "t", "text": "PHLPP and a second isoform, PHLPP2, differentially attenuate the amplitude of Akt signaling by regulating distinct Akt isoforms."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Cell (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.molcel.2007.02.017"}], "href": "https://doi.org/10.1016/j.molcel.2007.02.017"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "17386267"}], "href": "https://pubmed.ncbi.nlm.nih.gov/17386267"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Tianyan Gao, John Brognard, Alexandra C Newton "}, {"type": "b", "children": [{"type": "t", "text": "The phosphatase PHLPP controls the cellular levels of protein kinase C."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2008)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M707319200"}], "href": "https://doi.org/10.1074/jbc.M707319200"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "18162466"}], "href": "https://pubmed.ncbi.nlm.nih.gov/18162466"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "John Brognard, Alexandra C Newton "}, {"type": "b", "children": [{"type": "t", "text": "PHLiPPing the switch on Akt and protein kinase C signaling."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Trends Endocrinol Metab (2008)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.tem.2008.04.001"}], "href": "https://doi.org/10.1016/j.tem.2008.04.001"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "18511290"}], "href": "https://pubmed.ncbi.nlm.nih.gov/18511290"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Muhan Chen, Christopher P Pratt, Martha E Zeeman, et al. 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