In vitro and in silico characterization of human PHOSPHO2 reveals its phospholipid phosphatase activity
- 1Aichi Cancer Center Research Institution
Abstract
Phosphatidic acid (PA) phosphatase (PAP) is an enzyme that plays a major role in lipid signaling by controlling the cellular levels of two lipid secondary messengers: its substrate, PA, and its product, diacylglycerol. Two types of mammalian PAPs have been reported to date. Type 1 PAP (PAP1) is an Mg2+-dependent, N-ethylmaleimide (NEM)-sensitive cytosolic enzyme (EC 3.1.3.4), whereas type 2 PAP (PAP2), also known as phospholipid phosphatase (PLPP) (EC 3.1.3.113), is an Mg2+--independent, NEM-insensitive transmembrane protein. PAP2 also hydrolyzes other bioactive lipids such as lyso-PA (LPA), sphingosine-1-phosphate (S1P), and ceramide-1-phosphate (C1P). Here, we purified human phosphatase orphan 2 (PHOSPHO2), a putative cytosolic phosphatase containing a haloacid dehalogenase-like domain, and characterized its enzymological properties in vitro. Purified PHOSPHO2 displays Mg2+--dependent, NEM-sensitive phosphatase activities toward PA, LPA, S1P, C1P, and glycerol-3-phosphate (G3P) in vitro. Moreover, PHOSPHO2 showed substrate selectivity for PA molecular species containing shorter saturated fatty acids such as lauric acid and myristic acid, or polyunsaturated fatty acids such as docosahexaenoic acid and arachidonic acid. The PAP activity of PHOSPHO2, but not its other phosphatase activities, was strongly enhanced in the presence of phosphatidylcholine and phosphatidylethanolamine, major components of the cell membranes. These results indicate that mammalian PHOSPHO2 is a novel cytosolic PLPP that primarily functions as a PAP on cytoplasm-facing membranes.
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BibTeX
@misc{tsunoda2026vitro,
title = {{In vitro and in silico characterization of human PHOSPHO2 reveals its phospholipid phosphatase activity}},
author = {K. A. Tsunoda and C. Murakami and H. Sakai and F. Sakane},
howpublished = {bioRxiv},
year = {2026},
month = jul,
doi = {10.64898/2026.07.31.742009},
url = {https://www.biorxiv.org/content/10.64898/2026.07.31.742009v4},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - In vitro and in silico characterization of human PHOSPHO2 reveals its phospholipid phosphatase activity
AU - K. A. Tsunoda
AU - C. Murakami
AU - H. Sakai
AU - F. Sakane
PY - 2026
DA - 2026/07/31
PB - bioRxiv
DO - 10.64898/2026.07.31.742009
UR - https://www.biorxiv.org/content/10.64898/2026.07.31.742009v4
AB - Phosphatidic acid (PA) phosphatase (PAP) is an enzyme that plays a major role in lipid signaling by controlling the cellular levels of two lipid secondary messengers: its substrate, PA, and its product, diacylglycerol. Two types of mammalian PAPs have been reported to date. Type 1 PAP (PAP1) is an Mg2+-dependent, N-ethylmaleimide (NEM)-sensitive cytosolic enzyme (EC 3.1.3.4), whereas type 2 PAP (PAP2), also known as phospholipid phosphatase (PLPP) (EC 3.1.3.113), is an Mg2+--independent, NEM-insensitive transmembrane protein. PAP2 also hydrolyzes other bioactive lipids such as lyso-PA (LPA), sphingosine-1-phosphate (S1P), and ceramide-1-phosphate (C1P). Here, we purified human phosphatase orphan 2 (PHOSPHO2), a putative cytosolic phosphatase containing a haloacid dehalogenase-like domain, and characterized its enzymological properties in vitro. Purified PHOSPHO2 displays Mg2+--dependent, NEM-sensitive phosphatase activities toward PA, LPA, S1P, C1P, and glycerol-3-phosphate (G3P) in vitro. Moreover, PHOSPHO2 showed substrate selectivity for PA molecular species containing shorter saturated fatty acids such as lauric acid and myristic acid, or polyunsaturated fatty acids such as docosahexaenoic acid and arachidonic acid. The PAP activity of PHOSPHO2, but not its other phosphatase activities, was strongly enhanced in the presence of phosphatidylcholine and phosphatidylethanolamine, major components of the cell membranes. These results indicate that mammalian PHOSPHO2 is a novel cytosolic PLPP that primarily functions as a PAP on cytoplasm-facing membranes.
ER -