Phosphoinositide-binding activity of Smad2 is essential for its function in TGF-β signaling

Buwaneka, Pawanthi; Ralko, Arthur; Gorai, Sukhamoy; Phạm, Hà; Cho, Wonhwa

doi:10.1016/j.jbc.2021.101303

Cited by 6 publications

(4 citation statements)

References 56 publications

(138 reference statements)

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“…Therefore, LSS might induce a set of SMAD-co-factor complexes different than in HSS. Interestingly, a very recent study showed that SMAD proteins interact with membrane lipids via their MH2 domain [ 82 ]. The authors showed that SMAD2 preferentially binds to phosphatidylinositol-4,5-bisphosphate (PI(4,5)P 2 ) which accumulates at the plasma membrane (PM) rather than at EEs.…”

Section: Discussionmentioning

confidence: 99%

Atheroprone fluid shear stress-regulated ALK1-Endoglin-SMAD signaling originates from early endosomes

et al. 2022

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Background Fluid shear stress enhances endothelial SMAD1/5 signaling via the BMP9-bound ALK1 receptor complex supported by the co-receptor Endoglin. While moderate SMAD1/5 activation is required to maintain endothelial quiescence, excessive SMAD1/5 signaling promotes endothelial dysfunction. Increased BMP signaling participates in endothelial-to-mesenchymal transition and inflammation culminating in vascular diseases such as atherosclerosis. While the function of Endoglin has so far been described under picomolar concentrations of BMP9 and short-term shear application, we investigated Endoglin under physiological BMP9 and long-term pathophysiological shear conditions. Results We report here that knock-down of Endoglin leads to exacerbated SMAD1/5 phosphorylation and atheroprone gene expression profile in HUVECs sheared for 24 h. Making use of the ligand-trap ALK1-Fc, we furthermore show that this increase is dependent on BMP9/10. Mechanistically, we reveal that long-term exposure of ECs to low laminar shear stress leads to enhanced Endoglin expression and endocytosis of Endoglin in Caveolin-1-positive early endosomes. In these endosomes, we could localize the ALK1-Endoglin complex, labeled BMP9 as well as SMAD1, highlighting Caveolin-1 vesicles as a SMAD signaling compartment in cells exposed to low atheroprone laminar shear stress. Conclusions We identified Endoglin to be essential in preventing excessive activation of SMAD1/5 under physiological flow conditions and Caveolin-1-positive early endosomes as a new flow-regulated signaling compartment for BMP9-ALK1-Endoglin signaling axis in atheroprone flow conditions.

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Section: Discussionmentioning

confidence: 99%

Atheroprone fluid shear stress-regulated ALK1-Endoglin-SMAD signaling originates from early endosomes

et al. 2022

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“…All SPR measurements were performed at 23°C in 20 mM Tris, pH 7.4, containing 0.16 M NaCl using a lipid-coated L1 chip in the BIACORE X100 system (Cytiva) as described previously (Buwaneka et al, 2021; Park et al, 2016). LUVs of POPC/POPS/PI(3,5)P 2 (77:20:3) and POPC/POPS (80:20) were used as the active surface and the control surface, respectively.…”

Section: Methods Detailsmentioning

confidence: 99%

PI(3,5)P₂Controls the Signaling Activity of Class I PI3K

Sun

Song

Singaram

et al. 2023

Preprint

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3-Phosphoinositides are ubiquitous cellular lipids that play pivotal regulatory roles in health and disease. Generation of 3-phosphoinositides are driven by three families of phosphoinositide 3-kinases (PI3K) but the mechanisms underlying their regulation and cross-talk are not fully understood. Among 3-phosphoinositides, phosphatidylinositol-3,5‐bisphosphate (PI(3,5)P2) remains the least understood species in terms of its spatiotemporal dynamics and physiological function due to the lack of specific probes. By means of spatiotemporally resolved in situ quantitative imaging of PI(3,5)P2 using a newly developed ratiometric PI(3,5)P2 sensor we demonstrate that a special pool of PI(3,5)P2 is generated on lysosomes and late endosomes in response to growth factor stimulation. This PI(3,5)P2 pool, the formation of which is mediated by Class II PI3KC2β and PIKFyve, plays a crucial role in terminating the activity of growth factor-stimulated Class I PI3K, one of the most frequently mutated proteins in cancer, via specific interaction with its regulatory p85 subunit. Cancer-causing mutations of Class I PI3K inhibit the p85-PI(3,5)P2 interaction and thereby induce sustained activation of Class I PI3K. Our results unravel a hitherto unknown tight regulatory interplay between Class I and II PI3Ks mediated by PI(3,5)P2, which may be important for controlling the strength of PI3K-mediated growth factor signaling. These results also suggest a new therapeutic possibility of treating cancer patients with p85 mutations.

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“…All surface plasmon resonance (SPR) measurements were performed at 23°C in a degassed 20 mM Tris, pH 7.4, buffer solution containing 0.16 M NaCl using a lipid-coated L1 chip in the BIACORE X100 system (Cytiva) as described previously ( 28 , 29 ). Large unilamellar vesicles (LUVs) with an average diameter of 100 nm were prepared by extrusion through a 100-nm diameter polycarbonate membrane (Avanti Polar Lipids) in an Avanti Mini-Extruder (Avanti Polar Lipids) as described previously ( 30 ).…”

Section: Methodsmentioning

confidence: 99%

Development of a novel spatiotemporal depletion system for cellular cholesterol

Phạm

Singaram

Sun

et al. 2022

Journal of Lipid Research

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Phosphoinositide-binding activity of Smad2 is essential for its function in TGF-β signaling

Cited by 6 publications

References 56 publications

Atheroprone fluid shear stress-regulated ALK1-Endoglin-SMAD signaling originates from early endosomes

Atheroprone fluid shear stress-regulated ALK1-Endoglin-SMAD signaling originates from early endosomes

PI(3,5)P₂Controls the Signaling Activity of Class I PI3K

Development of a novel spatiotemporal depletion system for cellular cholesterol

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Phosphoinositide-binding activity of Smad2 is essential for its function in TGF-β signaling

Cited by 6 publications

References 56 publications

Atheroprone fluid shear stress-regulated ALK1-Endoglin-SMAD signaling originates from early endosomes

Atheroprone fluid shear stress-regulated ALK1-Endoglin-SMAD signaling originates from early endosomes

PI(3,5)P2Controls the Signaling Activity of Class I PI3K

Development of a novel spatiotemporal depletion system for cellular cholesterol

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Product

Resources

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PI(3,5)P₂Controls the Signaling Activity of Class I PI3K