scholarly journals Loss of PI3-kinase activity of inositol polyphosphate multikinase impairs PDK1-mediated AKT activation, cell migration and intestinal homeostasis

2020 ◽  
Author(s):  
Prasun Guha ◽  
Luke Reilly ◽  
Evan R. Semenza ◽  
Efrat Abramson ◽  
Subrata Mishra ◽  
...  
Keyword(s):  
Cell Migration ◽  
Epithelial Cell ◽  
Kinase Activity ◽  
Pi3 Kinase ◽  
Membrane Localization ◽  
Intestinal Epithelial ◽  
Inositol Polyphosphate ◽  
Akt Activation ◽  
Inositol Polyphosphate Multikinase ◽  
Mlc Phosphorylation

AbstractInositol polyphosphate multikinase (IPMK) is a rate-limiting enzyme in the inositol phosphate (IP) pathway which converts IP3 to IP4 and IP5. In mammalian cells, IPMK can also act as a phosphoinositol-3-kinase (PI3-kinase). We previously found that IPMK is a critical PI3-kinase activator of AKT. Here, we show that IPMK mediates AKT activation by promoting membrane localization and activation of PDK1. The PI3-kinase activity of IPMK is dispensable for membrane localization of AKT, which is entirely controlled by classical PI3-kinase (p110α,ß, γ, δ). By contrast, we found that PDK1 membrane localization was largely independent of classical PI3-kinase. Membrane localization of PDK1 stimulates cell migration by dissociating ROCK1 from inhibitory binding to RhoE and promoting ROCK1-mediated myosin light chain (MLC) phosphorylation. Deletion of IPMK impairs cell migration associated with the abolition of PDK1-mediated ROCK1 disinhibition and subsequent MLC phosphorylation. To investigate the physiological relevance of IPMK-mediated AKT activation, we generated mice selectively lacking IPMK in epithelial cells of the intestine, where IPMK is highly expressed. Deletion of IPMK in intestinal epithelial cells markedly reduced AKT phosphorylation and diminished numbers of Paneth cells – a crypt-resident epithelial cell type that generates the physiological niche for intestinal stem cells. Ablation of IPMK impaired intestinal epithelial cell regeneration basally and after; chemotherapy-induced damage, suggesting a broad role for IPMK in the activation of AKT and intestinal tissue regeneration. In summary, the PI3-kinase activity of IPMK promotes membrane localization of PDK1, a critical kinase whereby AKT maintains intestinal homeostasis.One Sentence SummaryPI3-kinase activity of IPMK is essential for activation of AKT.

Polyamines regulate Rho-kinase and myosin phosphorylation during intestinal epithelial restitution

2003 ◽  
Vol 284 (4) ◽  
pp. C848-C859 ◽  
Author(s):  
Jaladanki N. Rao ◽  
Xin Guo ◽  
Lan Liu ◽  
Tongtong Zou ◽  
Karnam S. Murthy ◽  
...  
Keyword(s):  
Cell Migration ◽  
Kinase Activity ◽  
Rho Kinase ◽  
Specific Inhibitor ◽  
Fiber Formation ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Intestinal Epithelial ◽  
Epithelial Restitution ◽  
Mlc Phosphorylation

Polyamines are required for the early phase of mucosal restitution that occurs as a consequence of epithelial cell migration. Our previous studies have shown that polyamines increase RhoA activity by elevating cytosolic free Ca2+ concentration ([Ca2+]cyt) through controlling voltage-gated K+ channel expression and membrane potential ( E m) during intestinal epithelial restitution. The current study went further to determine whether increased RhoA following elevated [Ca2+]cyt activates Rho-kinase (ROK/ROCK) resulting in myosin light chain (MLC) phosphorylation. Studies were conducted in stable Cdx2-transfected intestinal epithelial cells (IEC-Cdx2L1), which were associated with a highly differentiated phenotype. Reduced [Ca2+]cyt, by either polyamine depletion or exposure to the Ca2+-free medium, decreased RhoA protein expression, which was paralleled by significant decreases in GTP-bound RhoA, ROCK-1, and ROKα proteins, Rho-kinase activity, and MLC phosphorylation. The reduction of [Ca2+]cyt also inhibited cell migration after wounding. Elevation of [Ca2+]cyt induced by the Ca2+ ionophore ionomycin increased GTP-bound RhoA, ROCK-1, and ROKα proteins, Rho-kinase activity, and MLC phosphorylation. Inhibition of RhoA function by a dominant negative mutant RhoA decreased the Rho-kinase activity and resulted in cytoskeletal reorganization. Inhibition of ROK/ROCK activity by the specific inhibitor Y-27632 not only decreased MLC phosphorylation but also suppressed cell migration. These results indicate that increase in GTP-bound RhoA by polyamines via [Ca2+]cytcan interact with and activate Rho-kinase during intestinal epithelial restitution. Activation of Rho-kinase results in increased MLC phosphorylation, leading to the stimulation of myosin stress fiber formation and cell migration.

scholarly journals Huntington’s disease: Neural dysfunction linked to inositol polyphosphate multikinase

2015 ◽  
Vol 112 (31) ◽  
pp. 9751-9756 ◽  
Author(s):  
Ishrat Ahmed ◽  
Juan I. Sbodio ◽  
Maged M. Harraz ◽  
Richa Tyagi ◽  
Jonathan C. Grima ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Kinase Activity ◽  
Inositol Phosphate ◽  
Cell Model ◽  
Inositol Polyphosphate ◽  
Interacting Protein ◽  
Lipid Kinase ◽  
Inositol Polyphosphate Multikinase ◽  
Neural Dysfunction

Huntington’s disease (HD) is a progressive neurodegenerative disease caused by a glutamine repeat expansion in mutant huntingtin (mHtt). Despite the known genetic cause of HD, the pathophysiology of this disease remains to be elucidated. Inositol polyphosphate multikinase (IPMK) is an enzyme that displays soluble inositol phosphate kinase activity, lipid kinase activity, and various noncatalytic interactions. We report a severe loss of IPMK in the striatum of HD patients and in several cellular and animal models of the disease. This depletion reflects mHtt-induced impairment of COUP-TF-interacting protein 2 (Ctip2), a striatal-enriched transcription factor for IPMK, as well as alterations in IPMK protein stability. IPMK overexpression reverses the metabolic activity deficit in a cell model of HD. IPMK depletion appears to mediate neural dysfunction, because intrastriatal delivery of IPMK abates the progression of motor abnormalities and rescues striatal pathology in transgenic murine models of HD.

scholarly journals Inositol polyphosphate multikinase is a metformin target that regulates cell migration

2019 ◽  
Vol 33 (12) ◽  
pp. 14137-14146 ◽  
Author(s):  
Becky Tu-Sekine ◽  
Abinash Padhi ◽  
Sunghee Jin ◽  
Srivathsan Kalyan ◽  
Karanpreet Singh ◽  
...  
Keyword(s):  
Cell Migration ◽  
Inositol Polyphosphate ◽  
Inositol Polyphosphate Multikinase

scholarly journals Role of K+ channel expression in polyamine-dependent intestinal epithelial cell migration

2000 ◽  
Vol 278 (2) ◽  
pp. C303-C314 ◽  
Author(s):  
Jian-Ying Wang ◽  
Jian Wang ◽  
Vera A. Golovina ◽  
Li Li ◽  
Oleksandr Platoshyn ◽  
...  
Keyword(s):  
Cell Migration ◽  
Epithelial Cell ◽  
Driving Force ◽  
Intestinal Epithelial Cell ◽  
Delayed Rectifier ◽  
Intestinal Epithelial ◽  
Voltage Gated ◽  
Epithelial Cell Migration ◽  
Channel Expression ◽  
Exogenous Spermidine

Polyamines are essential for cell migration during early mucosal restitution after wounding in the gastrointestinal tract. Activity of voltage-gated K+ channels (Kv) controls membrane potential ( E m) that regulates cytoplasmic free Ca2+ concentration ([Ca2+]cyt) by governing the driving force for Ca2+ influx. This study determined whether polyamines are required for the stimulation of cell migration by altering K+ channel gene expression, E m, and [Ca2+]cyt in intestinal epithelial cells (IEC-6). The specific inhibitor of polyamine synthesis, α-difluoromethylornithine (DFMO, 5 mM), depleted cellular polyamines (putrescine, spermidine, and spermine), selectively inhibited Kv1.1 channel (a delayed-rectifier Kv channel) expression, and resulted in membrane depolarization. Because IEC-6 cells did not express voltage-gated Ca2+ channels, the depolarized E m in DFMO-treated cells decreased [Ca2+]cyt as a result of reduced driving force for Ca2+ influx through capacitative Ca2+ entry. Migration was reduced by 80% in the polyamine-deficient cells. Exogenous spermidine not only reversed the effects of DFMO on Kv1.1 channel expression, E m, and [Ca2+]cyt but also restored cell migration to normal. Removal of extracellular Ca2+ or blockade of Kv channels (by 4-aminopyridine, 1–5 mM) significantly inhibited normal cell migration and prevented the restoration of cell migration by exogenous spermidine in polyamine-deficient cells. These results suggest that polyamine-dependent intestinal epithelial cell migration may be due partially to an increase of Kv1.1 channel expression. The subsequent membrane hyperpolarization raises [Ca2+]cyt by increasing the driving force (the electrochemical gradient) for Ca2+ influx and thus stimulates cell migration.

scholarly journals Ursodeoxycholic acid protects against intestinal barrier breakdown by promoting enterocyte migration via EGFR- and COX-2-dependent mechanisms

2018 ◽  
Vol 315 (2) ◽  
pp. G259-G271 ◽  
Author(s):  
Jamie M. Golden ◽  
Oswaldo H. Escobar ◽  
Michelle V. L. Nguyen ◽  
Michael U. Mallicote ◽  
Patil Kavarian ◽  
...  
Keyword(s):  
Cell Migration ◽  
Epithelial Cell ◽  
Ursodeoxycholic Acid ◽  
Intestinal Epithelial Cell ◽  
Growth Factor Receptor ◽  
Intestinal Barrier ◽  
Intestinal Epithelial ◽  
Epithelial Cell Migration ◽  
Cox 2

The intestinal barrier is often disrupted in disease states, and intestinal barrier failure leads to sepsis. Ursodeoxycholic acid (UDCA) is a bile acid that may protect the intestinal barrier. We hypothesized that UDCA would protect the intestinal epithelium in injury models. To test this hypothesis, we utilized an in vitro wound-healing assay and a mouse model of intestinal barrier injury. We found that UDCA stimulates intestinal epithelial cell migration in vitro, and this migration was blocked by inhibition of cyclooxygenase 2 (COX-2), epidermal growth factor receptor (EGFR), or ERK. Furthermore, UDCA stimulated both COX-2 induction and EGFR phosphorylation. In vivo UDCA protected the intestinal barrier from LPS-induced injury as measured by FITC dextran leakage into the serum. Using 5-bromo-2′-deoxyuridine and 5-ethynyl-2′-deoxyuridine injections, we found that UDCA stimulated intestinal epithelial cell migration in these animals. These effects were blocked with either administration of Rofecoxib, a COX-2 inhibitor, or in EGFR-dominant negative Velvet mice, wherein UDCA had no effect on LPS-induced injury. Finally, we found increased COX-2 and phosphorylated ERK levels in LPS animals also treated with UDCA. Taken together, these data suggest that UDCA can stimulate intestinal epithelial cell migration and protect against acute intestinal injury via an EGFR- and COX-2-dependent mechanism. UDCA may be an effective treatment to prevent the early onset of gut-origin sepsis. NEW & NOTEWORTHY In this study, we show that the secondary bile acid ursodeoxycholic acid stimulates intestinal epithelial cell migration after cellular injury and also protects the intestinal barrier in an acute rodent injury model, neither of which has been previously reported. These effects are dependent on epidermal growth factor receptor activation and downstream cyclooxygenase 2 upregulation in the small intestine. This provides a potential treatment for acute, gut-origin sepsis as seen in diseases such as necrotizing enterocolitis.

scholarly journals Inositol polyphosphate multikinase is a physiologic PI3-kinase that activates Akt/PKB

2011 ◽  
Vol 108 (4) ◽  
pp. 1391-1396 ◽  
Author(s):  
D. Maag ◽  
M. J. Maxwell ◽  
D. A. Hardesty ◽  
K. L. Boucher ◽  
N. Choudhari ◽  
...  
Keyword(s):  
Pi3 Kinase ◽  
Inositol Polyphosphate ◽  
Inositol Polyphosphate Multikinase
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