scholarly journals PCTK1 Regulates Integrin-Dependent Spindle Orientation via Protein Kinase A Regulatory Subunit KAP0 and Myosin X

2015 ◽  
Vol 35 (7) ◽  
pp. 1197-1208 ◽  
Author(s):  
Sayaka Iwano ◽  
Ayaka Satou ◽  
Shigeru Matsumura ◽  
Naoyuki Sugiyama ◽  
Yasushi Ishihama ◽  
...  

Integrin-dependent cell-extracellular matrix (ECM) adhesion is a determinant of spindle orientation. However, the signaling pathways that couple integrins to spindle orientation remain elusive. Here, we show that PCTAIRE-1 kinase (PCTK1), a member of the cyclin-dependent kinases (CDKs) whose function is poorly characterized, plays an essential role in this process. PCTK1 regulates spindle orientation in a kinase-dependent manner. Phosphoproteomic analysis together with an RNA interference screen revealed that PCTK1 regulates spindle orientation through phosphorylation of Ser83 on KAP0, a regulatory subunit of protein kinase A (PKA). This phosphorylation is dispensable for KAP0 dimerization and for PKA binding but is necessary for its interaction with myosin X, a regulator of spindle orientation. KAP0 binds to the FERM domain of myosin X and enhances the association of myosin X-FERM with β1 integrin. This interaction between myosin X-FERM and β1 integrin appeared to be crucial for spindle orientation control. We propose that PCTK1-KAP0-myosin X-β1 integrin is a functional module providing a link between ECM and the actin cytoskeleton in the ECM-dependent control of spindle orientation.

2021 ◽  
Author(s):  
Rebecca LaCroix ◽  
Benjamin Lin ◽  
Andre Levchenko

SummaryKinase activity in signaling networks frequently depends on regulatory subunits that can both inhibit activity by interacting with the catalytic subunits and target the kinase to distinct molecular partners and subcellular compartments. Here, using a new synthetic molecular interaction system, we show that translocation of a regulatory subunit of the protein kinase A (PKA-R) to the plasma membrane has a paradoxical effect on the membrane kinase activity. It can both enhance it at lower translocation levels, even in the absence of signaling inputs, and inhibit it at higher translocation levels, suggesting its role as a linker that can both couple and decouple signaling processes in a concentration-dependent manner. We further demonstrate that superposition of gradients of PKA-R abundance across single cells can control the directionality of cell migration, reversing it at high enough input levels. Thus complex in vivo patterns of PKA-R localization can drive complex phenotypes, including cell migration.


2015 ◽  
Vol 36 (3) ◽  
pp. 866-883 ◽  
Author(s):  
Annika Sommerfeld ◽  
Roland Reinehr ◽  
Dieter Häussinger

Background/Aims: Ursodeoxycholic acid, which in vivo is rapidly converted into its taurine conjugate, is frequently used for the treatment of cholestatic liver disease. Apart from its choleretic effects, tauroursodeoxycholate (TUDC) can protect hepatocytes from bile acid-induced apoptosis, but the mechanisms underlying its anti-apoptotic effects are poorly understood. Methods: These mechanisms were investigated in perfused rat liver and isolated rat hepatocytes. Results: It was found that TUDC inhibited the glycochenodeoxycholate (GCDC)-induced activation of the CD95 death receptor at the level of association between CD95 and the epidermal growth factor receptor. This was due to a rapid TUDC-induced β1-integrin-dependent cyclic AMP (cAMP) signal with induction of the dual specificity mitogen-activated protein (MAP) kinase phosphatase 1 (MKP-1), which prevented GCDC-induced phosphorylation of mitogen-activated protein kinase kinase 4 (MKK4) and c-jun-NH2-terminal kinase (JNK) activation. Furthermore, TUDC induced a protein kinase A (PKA)-mediated serine/threonine phosphorylation of the CD95, which was recently identified as an internalization signal for CD95. Furthermore, TUDC inhibited GCDC-induced CD95 targeting to the plasma membrane in a β1-integrin-and PKA-dependent manner. In line with this, the β1-integrin siRNA knockdown in sodium taurocholate cotransporting polypeptide (Ntcp)-transfected HepG2 cells abolished the protective effect of TUDC against GCDC-induced apoptosis. Conclusion: TUDC exerts its anti-apoptotic effect via a β1-integrin-mediated formation of cAMP, which prevents CD95 activation by hydrophobic bile acids at the levels of JNK activation and CD95 serine/threonine phosphorylation.


2007 ◽  
Vol 18 (7) ◽  
pp. 2745-2754 ◽  
Author(s):  
Kacper A. Wojtal ◽  
Dick Hoekstra ◽  
Sven C.D. van IJzendoorn

Oncostatin M and cAMP signaling stimulate apical surface-directed membrane trafficking and apical lumen development in hepatocytes, both in a protein kinase A (PKA)-dependent manner. Here, we show that oncostatin M, but not cAMP, promotes the A-kinase anchoring protein (AKAP)-dependent anchoring of the PKA regulatory subunit (R)IIα to subapical centrosomes and that this requires extracellular signal-regulated kinase 2 activation. Stable expression of the RII-displacing peptide AKAP-IS, but not a scrambled peptide, inhibits the association of RIIα with centrosomal AKAPs and results in the repositioning of the centrosome from a subapical to a perinuclear location. Concomitantly, common endosomes, but not apical recycling endosomes, are repositioned from a subapical to a perinuclear location, without significant effects on constitutive or oncostatin M-stimulated basolateral-to-apical transcytosis. Importantly, however, the expression of the AKAP-IS peptide completely blocks oncostatin M-, but not cAMP-stimulated apical lumen development. Together, the data suggest that centrosomal anchoring of RIIα and the interrelated subapical positioning of these centrosomes is required for oncostatin M-, but not cAMP-mediated, bile canalicular lumen development in a manner that is uncoupled from oncostatin M-stimulated apical lumen-directed membrane trafficking. The results also imply that multiple PKA-mediated signaling pathways control apical lumen development and that subapical centrosome positioning is important in some of these pathways.


Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1361
Author(s):  
Maira Zorzan ◽  
Claudia Del Vecchio ◽  
Stefania Vogiatzis ◽  
Elisa Saccon ◽  
Cristina Parolin ◽  
...  

Glioblastoma is the most malignant and most common form of brain tumor, still today associated with a poor 14-months median survival from diagnosis. Protein kinase A, particularly its regulatory subunit R2Alpha, presents a typical intracellular distribution in glioblastoma cells compared to the healthy brain parenchyma and this peculiarity might be exploited in a therapeutic setting. In the present study, a third-generation lentiviral system for delivery of shRNA targeting the regulatory subunit R2Alpha of protein kinase A was developed. Generated lentiviral vectors are able to induce an efficient and stable downregulation of R2Alpha in different cellular models, including non-stem and stem-like glioblastoma cells. In addition, our data suggest a potential correlation between silencing of the regulatory subunit of protein kinase A and reduced viability of tumor cells, apparently due to a reduction in replication rate. Thus, our findings support the role of protein kinase A as a promising target for novel anti-glioma therapies.


2021 ◽  
pp. 107732
Author(s):  
Nicolás González Bardeci ◽  
Enzo Tofolón ◽  
Felipe Trajtenberg ◽  
Julio Caramelo ◽  
Nicole Larrieux ◽  
...  

2004 ◽  
Vol 18 (9) ◽  
pp. 2302-2311 ◽  
Author(s):  
Michael A. Nolan ◽  
Maria A. Sikorski ◽  
G. Stanley McKnight

Abstract Mice lacking the RIIβ regulatory subunit of protein kinase A exhibit a 50% reduction in white adipose tissue stores compared with wild-type littermates and are resistant to diet-induced obesity. RIIβ−/− mice also have an increase in resting oxygen consumption along with a 4-fold increase in the brown adipose-specific mitochondrial uncoupling protein 1 (UCP1). In this study, we examined the basis for UCP1 induction and tested the hypothesis that the induced levels of UCP1 in RIIβ null mice are essential for the lean phenotype. The induction of UCP1 occurred at the protein but not the mRNA level and correlated with an increase in mitochondria in brown adipose tissue. Mice lacking both RIIβ and UCP1 (RIIβ−/−/Ucp1−/−) were created, and the key parameters of metabolism and body composition were studied. We discovered that RIIβ−/− mice exhibit nocturnal hyperactivity in addition to the increased oxygen consumption at rest. Disruption of UCP1 in RIIβ−/− mice reduced basal oxygen consumption but did not prevent the nocturnal hyperactivity. The double knockout animals also retained the lean phenotype of the RIIβ null mice, demonstrating that induction of UCP1 and increased resting oxygen consumption is not the cause of leanness in the RIIβ mutant mice.


Biologia ◽  
2015 ◽  
Vol 70 (10) ◽  
Author(s):  
Yu Zhang ◽  
Pu Feng ◽  
Jianhong Yang

AbstractIncreased risk of osteoporosis in patients with diabetes mellitus may be related to hyperglycemia. However, the potential mechanisms accounting for diabetic bone disorder remain unresolved. The present study investigated the effects of high glucose-associated osmolality on differentiation of primary rat calvarial osteoblasts. Osteoblastogenic differentiation was determined by bone nodule staining for mineralization assay, enzyme-linked immunosorbent assay for type I collagen production and real-time polymerase chain reaction (PCR) for osteoblastogenic marker gene expression. Adipocytogenic differentiation was assessed by oil red O staining for lipid accumulation and real-time PCR for adipocytogenic marker gene expression. The phosphorylations of protein kinase A (PKA) and Akt were measured with or without specific inhibitors to confirm osmolality involved signalling pathways. The results showed that high glucose-associated osmolality significantly promoted adipocytogenic differentiation, manifested by increased lipid droplet formation and gene expression of adipocytogenic markers including adipocyte fatty acid binding protein (aP2), adipsin and peroxisome proliferator-activated receptor gamma (PPARγ). Meanwhile, high glucose-associated osmolality inhibited osteoblastogenic differentiation, characterized by decreased collagen I protein production and cell mineralization, as well as gene expression of osteoblastogenic markers including collagen I, osteocalcin and runt-related transcription factor 2 (Runx2). More importantly, we demonstrated for the first time that high glucose-associated osmolality induced adipocytogenic differentiation and suppressed osteoblastogenic differentiation in a PKA and phosphatidylinositol 3-kinase (PI3K)/Akt-dependent manner. These results indicated that osmolality was involved in high glucose-induced osteoblast trans-differentiation into adipocyte-like cell and suppression of cellular osmolality could provide novel therapeutic approach for diabetic osteopenia.


1997 ◽  
Vol 272 (1) ◽  
pp. C82-C89 ◽  
Author(s):  
S. Ledoux ◽  
J. C. Dussaule ◽  
C. Chatziantoniou ◽  
N. Ardaillou ◽  
S. Vandermeersch ◽  
...  

The purpose of this work was to examine whether the level of cAMP accumulation and protein kinase A (PKA) activity influence atrial natriuretic factor (ANF)-dependent guanosine 3',5'-cyclic monophosphate (cGMP) production in two renal cell types: rabbit cortical vascular smooth muscle cells (RCSMC) and SV-40-transformed human glomerular visceral epithelial cells (HGVEC-SV1). N-[2-(p-bromocinnamylamino)ethyl]- 5-isoquinolinesulfonamide (H-89), a PKA inhibitor, decreased ANF-stimulated cGMP production in RCSMC in a time- and concentration-dependent manner. ANF-stimulated cGMP production was markedly inhibited after prolonged 9- and 18-h incubations with 25 microM H-89 (52 and 65%, respectively) but was not altered after exposure of cells to this agent for 1 h. 1-(5-Isoquinolinylsulfonyl)-2-methylpiperazine and N-(2-[methylamino]ethyl)-5-isoquinolinesulfonamide, protein kinase inhibitors not selective for PKA, did not reproduce the effect of H-89, even at higher concentrations (50 and 100 microM). Cycloheximide (10 microM), a protein synthesis inhibitor, limited the inhibitory effect of H-89, although alone it did not modify the ANF-stimulated cGMP production. H-89 did not affect cGMP production when it was stimulated by SIN-1, a nitric oxide donor. Prolonged incubation (18 h) with 8-bromo cAMP or cholera toxin, an activator of Gs protein resulting in adenylate cyclase stimulation, enhanced ANF-dependent cGMP production by 225 and 176%, respectively. This stimulatory effect was blocked by 25 microM H-89. 125I-ANF binding to RCSMC at 4 degrees C was not affected by preincubation of the cells with H-89. There was a 44% decrease in the expression of ANF C receptors measured as the ANF-(4-23)-displaceable 125I-ANF binding at 37 degrees C, which could not, however, explain the inhibitory effect of H-89 on cGMP production. Modulation of ANF- and C-type natriuretic peptide-dependent cGMP production by H-89 and cholera toxin was also found in HGVEC-SV1 with the same characteristics as in RCSMC. Taken together, these results suggest that PKA activity controls the function of natriuretic peptide guanylate cyclase-coupled receptors in the two cell types studied. PKA-dependent inhibition of a negatively regulatory protein distinct from the receptor itself seems necessary for a full cGMP response.


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