| 2021 |
Cryo-EM structures reveal that CTP regulates both CTPS1 and CTPS2 by binding in two sites that clash with substrates (product feedback inhibition). CTPS1 is less sensitive to CTP feedback inhibition than CTPS2, consistent with its role in expanding CTP pools during lymphocyte proliferation. Small-molecule inhibitors that are CTPS1-selective or non-selective mimic CTP binding at one inhibitory site, with a single amino acid substitution explaining isoform selectivity. Both inhibitors bind to CTPS1 assembled into large-scale filaments, which represent a hyperactive form of the enzyme. |
Cryo-electron microscopy (cryo-EM) structures of inhibitor-bound and CTP-bound CTPS1 filaments; biochemical inhibition assays; site-directed mutagenesis (amino acid substitution analysis); primary T cell proliferation assay |
Proceedings of the National Academy of Sciences of the United States of America |
High |
34583994
|
| 2020 |
CTPS1 deficiency caused by homozygous frameshift splice mutation (c.1692-1G>C, p.T566Dfs26X) results in 80–90% reduction of CTPS protein and CTP synthetase activity in patient lymphocytes, leading to severely impaired T cell proliferation and IL-2 secretion upon TCR activation. The mutant protein (T566Dfs26X) retains normal CTPS enzymatic activity when expressed at wild-type levels; loss of function is entirely attributable to protein instability. Inactivation of CTPS1 in a T cell leukemia line fully abolished proliferation, confirming CTPS1 is required for T cell proliferative responses. |
CTPS enzymatic activity assay in patient cells; genetic complementation in CTPS1-deficient leukemia cells with WT and mutant constructs; immune phenotyping; T cell proliferation and IL-2 secretion assays |
JCI insight |
High |
32161190
|
| 2023 |
CTPS1 has higher intrinsic CTP synthetase enzymatic activity than CTPS2 and is more resistant to inhibition by the UTP analog 3-deaza-uridine. Using inactivation and complementation experiments, CTPS1 was shown to be the primary contributor to cell proliferation; CTPS2 contributes modestly when CTPS1 is present but is essential in its absence. |
CTPS1 and/or CTPS2 inactivation by KO; complementation experiments; in vitro enzymatic activity assays; 3-deaza-uridine inhibition assays; analysis of >1,000 cancer cell line datasets |
Life science alliance |
High |
37348953
|
| 2022 |
Inhibition of CTPS1 (but not CTPS2) selectively induces DNA replication stress in MYC-overexpressing cancer cells. MYC-driven rRNA synthesis causes selective replication stress upon CTPS1 inhibition. Combined inhibition of CTPS1 and ATR is synthetically lethal in MYC-overexpressing cells in vitro and decreases tumor growth in vivo. |
CTPS1/CTPS2-selective knockdown/inhibition; replication stress assays; cell viability assays; in vivo xenograft tumor models; ATR inhibitor combination studies |
Cancer research |
High |
35022212
|
| 2025 |
CTPS1 and CTPS2 directly interact with each other independently of polymerization and cytoophidium formation, forming heterocomplexes. When associated with CTPS2, CTPS1 enzymatic activity is decreased and becomes more sensitive to CTP product feedback inhibition, demonstrating that CTPS2 modulates CTPS1 activity through heterocomplex formation. CTPS2-containing filaments (cytoophidia) are dependent on CTPS1 expression. CTPS1H355A and CTPS2H355A mutants unable to form cytoophidia can still sustain normal cell proliferation, showing cytoophidia are not required for proliferation. |
Co-immunoprecipitation; enzymatic activity assays with purified complexes; CTPS1/CTPS2 KO and complementation; H355A cytoophidium-deficient mutant analysis; co-localization imaging |
Life science alliance |
High |
40957650
|
| 2025 |
CTP (the enzymatic product of CTPS1) acts as a key regulator driving hCTPS1 filamentation. Cryo-EM structures of CTP-bound hCTPS1 filaments reveal the molecular details of CTP binding in filament assembly. CTP generated from the enzymatic reaction does not trigger filament disassembly. Two distinct CTP-binding pockets mediate this filamentation, and the mechanism is evolutionarily conserved across eukaryotic CTPS. |
Cryo-electron microscopy (cryo-EM) of CTP-bound hCTPS1 filaments; biochemical filamentation assays; analysis of CTP-binding pocket mutants |
bioRxivpreprint |
Medium |
bio_10.1101_2025.02.22.639624
|
| 2024 |
RASD2 promotes SUMOylation of CTPS1 and inhibits its ubiquitination, thereby increasing CTPS1 protein stability. This was demonstrated by co-immunoprecipitation and immunoprecipitation-mass spectrometry in endometriosis cells, where histone lactylation upregulates RASD2, which in turn stabilizes CTPS1 via the SUMOylation/ubiquitination balance. |
Co-immunoprecipitation (Co-IP); immunoprecipitation-mass spectrometry (IP-MS); Western blot for ubiquitination and SUMOylation; ChIP-qPCR; in vitro and in vivo endometriosis models |
American journal of physiology. Cell physiology |
Medium |
39672102
|
| 2021 |
CTPS interacts with ATP synthase (ATPS) and maintains ATP content during early decidualization (Day 3). At Day 6 of decidualization, CTPS instead associates with mitochondrial stress protein STRESS-70, correlating with reduced ATP concentration. CTPS localization shifts from cytoplasm (Day 3) to both cytoplasm and nucleus (Day 6), suggesting subcellular redistribution is linked to metabolic function during the decidualization process. |
Co-immunoprecipitation coupled with mass spectrometry; subcellular fractionation/immunofluorescence localization; CTPS knockdown by siRNA; in vitro decidualization model |
Journal of cellular physiology |
Medium |
33576499
|
| 2024 |
CTPS1 upregulates expression of choline/ethanolamine phosphotransferase 1 (CEPT1) by increasing CTP availability, thereby reprogramming glycerophospholipid metabolism. Glycerophospholipids synthesized by CEPT1 maintain mitochondrial homeostasis and promote BNIP3-mediated mitophagy, driving DLBCL progression. |
CTPS1 knockout/knockdown; single-cell RNA sequencing; Western blot and gene expression analysis; selective CTPS1 inhibitor (R80); functional mitophagy assays |
Redox biology |
Medium |
41865720
|
| 2025 |
INHBA interacts with CTPS1 and competitively inhibits SMURF1 (SMAD Specific E3 Ubiquitin Protein Ligase 1)-mediated ubiquitination of CTPS1, thereby enhancing CTPS1 protein stability and promoting pyrimidine metabolism and gemcitabine resistance in pancreatic cancer cells. |
Immunoprecipitation mass spectrometry to identify CTPS1 as INHBA binding partner; Co-IP; in vitro ubiquitination assay; in vivo xenograft model |
Cancer cell international |
Medium |
41239468
|
| 2022 |
YBX1 (Y-box binding protein 1) directly binds to the CTPS1 promoter and activates its transcription, as demonstrated by dual luciferase reporter assays and chromatin immunoprecipitation (ChIP). Rescue experiments confirmed that enhanced cell proliferation and invasion driven by YBX1 overexpression could be reversed by CTPS1 knockdown, placing YBX1 upstream of CTPS1 in TNBC. |
Dual luciferase reporter assay; chromatin immunoprecipitation (ChIP); CTPS1 knockdown; YBX1 overexpression rescue experiment |
Journal of translational medicine |
Medium |
34991621
|
| 2023 |
CTPS1 pharmacological inhibition by STP-B in mantle cell lymphoma causes rapid cell cycle arrest in early S-phase, inhibition of translation including anti-apoptotic MCL1 protein, and synergistic cell death in combination with the BCL2 inhibitor venetoclax, both in vitro and in vivo. |
Selective CTPS1 inhibitor STP-B; flow cytometry cell cycle analysis; Western blot for MCL1; in vitro and in vivo MCL models; BCL2 inhibitor combination assay |
Haematologica |
Medium |
38385294
|
| 2023 |
CTPS1 knockout in multiple myeloma cells induces apoptosis and S-phase arrest with DNA double-strand breaks. Pharmacological inhibition of CTPS1 by STP-B activates DNA damage response (DDR) pathways. Combined inhibition of CTPS1 with ATR, CHEK1, or WEE1 inhibitors results in synergistic growth inhibition and early apoptosis. |
CTPS1 knockout; selective CTPS1 inhibitor STP-B; flow cytometry; DNA damage marker assays (γH2AX); DDR pathway inhibitor combinations; apoptosis assays |
Leukemia |
Medium |
37898670
|
| 2024 |
Single-molecule fluorescence imaging demonstrated that CTPS self-assembles with tetramers as the minimum structural unit driving cytoophidium formation. CTPS acts as the nucleation core to induce subsequent growth of P5CS (Δ1-pyrroline-5-carboxylate synthase) filaments, constituting a coassembly (coordinated assembly) process in vitro. |
Single-molecule fluorescence imaging; single-molecule photobleach counting for stoichiometry; oligomer state distribution analysis under different conditions; in vitro reconstitution of CTPS and P5CS coassembly |
The journal of physical chemistry. B |
Medium |
38236746
|
| 2025 |
HSPD1 (HSP60) interacts with CTPS protein; interference with Hspd1 gene expression inhibits CTPS cytoophidium formation even when CTPS is overexpressed, and this inhibits C2C12 skeletal muscle cell proliferation. The cytoophidium-deficient H355A CTPS mutant similarly inhibits proliferation. |
Co-immunoprecipitation (Co-IP) of HSPD1-CTPS; Hspd1 knockdown; CTPS overexpression; H355A mutation; EdU incorporation and viability assays |
Experimental cell research |
Low |
39971178
|