The Tumor Suppressor Gene H-Rev107 Functions As a Novel Ca2+-independent Cytosolic Phospholipase A1/2 of the Thiol Hydrolase Type
Overview
Affiliations
H-Rev107 is a protein that was previously cloned as a negative regulator of proto-oncogene Ras and classified as a class II tumor suppressor. Its structural similarity to lecithin retinol acyltransferase and Ca2+-independent phosphatidylethanolamine (PE) N-acyltransferase led us to analyze H-Rev107 as an enzyme involved in phospholipid metabolism. Here, we show that recombinant H-Rev107s from rat, human, and mouse possess phospholipase (PL) A1 or A2 activity toward phosphatidylcholine (PC). Further examination with purified recombinant protein revealed that H-Rev107 functions as a cytosolic Ca2+-independent PLA(1/2) for PC and PE with higher PLA1 activity than PLA2 activity. Dithiothreitol and iodoacetic acid exhibited stimulatory and inhibitory effects, respectively. Histidine-21 and cysteine-111 of rat H-Rev107 were presumed to form a catalytic dyad based on database analysis, and their single mutants were totally inactive. These results suggested that H-Rev107 is a hydrolase of the thiol type. The N-terminal proline-rich and C-terminal hydrophobic domains of H-Rev107 were earlier reported to be responsible for the regulation of cell proliferation. Analysis of deletion mutants indicated that these domains are also catalytically essential, suggesting relevance of the catalytic activity to the anti-proliferative activity.
Schuermans N, El Chehadeh S, Hemelsoet D, Gautheron J, Vantyghem M, Nouioua S Nat Genet. 2023; 55(11):1929-1940.
PMID: 37919452 DOI: 10.1038/s41588-023-01535-3.
Cytoplasmic Lipases-A Novel Class of Fungal Defense Proteins Against Nematodes.
Tayyrov A, Wei C, Fetz C, Goryachkin A, Schachle P, Nystrom L Front Fungal Biol. 2023; 2:696972.
PMID: 37744157 PMC: 10512399. DOI: 10.3389/ffunb.2021.696972.
Hung C, Yen J, Chang P, Chen L, Huang T, Tsai W Viruses. 2023; 15(3).
PMID: 36992520 PMC: 10053803. DOI: 10.3390/v15030812.
PLAAT1 inhibits type I interferon response degradation of IRF3 and IRF7 in Zebrafish.
Zhao X, Huang W, Shi Y, Guo J, Xiao H, Ji N Front Immunol. 2022; 13:979919.
PMID: 36172355 PMC: 9510373. DOI: 10.3389/fimmu.2022.979919.
Watanabe S, Nihongaki Y, Itoh K, Uyama T, Toda S, Watanabe S Nat Commun. 2022; 13(1):4413.
PMID: 35906209 PMC: 9338259. DOI: 10.1038/s41467-022-31946-5.