scholarly journals The p85α Subunit of Class IA Phosphatidylinositol 3-Kinase Regulates the Expression of Multiple Genes Involved in Osteoclast Maturation and Migration

2008 ◽  
Vol 28 (23) ◽  
pp. 7182-7198 ◽  
Author(s):  
Veerendra Munugalavadla ◽  
Sasidhar Vemula ◽  
Emily Catherine Sims ◽  
Subha Krishnan ◽  
Shi Chen ◽  
...  
Keyword(s):  
Full Length ◽  
Mitogen Activated Protein Kinase ◽  
Class I ◽  
Pcr Analysis ◽  
Tartrate Resistant Acid Phosphatase ◽  
Wild Type ◽  
Phosphatidylinositol 3 Kinase ◽  
And Migration ◽  
Phosphatidylinositol 3

ABSTRACT Intracellular signals involved in the maturation and function of osteoclasts are poorly understood. Here, we demonstrate that osteoclasts express multiple regulatory subunits of class IA phosphatidylinositol 3-kinase (PI3-K) although the expression of the full-length form of p85α is most abundant. In vivo, deficiency of p85α results in a significantly greater number of trabeculae and significantly lower spacing between trabeculae as well as increased bone mass in both males and females compared to their sex-matched wild-type controls. Consistently, p85α−/− osteoclast progenitors show impaired growth and differentiation, which is associated with reduced activation of Akt and mitogen-activated protein kinase extracellular signal-regulated kinase 1 (Erk1)/Erk2 in vitro. Furthermore, a significant reduction in the ability of p85α−/− osteoclasts to adhere to as well as to migrate via integrin αvβ3 was observed, which was associated with reduced bone resorption. Microarray as well as quantitative real-time PCR analysis of p85α−/− osteoclasts revealed a significant reduction in the expression of several genes associated with the maturation and migration of osteoclasts, including microphathalmia-associated transcription factor, tartrate-resistant acid phosphatase, cathepsin K, and β3 integrin. Restoring the expression of the full-length form of p85α but not the version with a deletion of the Src homology-3 domain restored the maturation of p85α−/− osteoclasts to wild-type levels. These results highlight the importance of the full-length version of the p85α subunit of class IA PI3-K in controlling multiple aspects of osteoclast functions.

scholarly journals Relative importance of phosphatidylinositol-3 kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK3/1) signaling during maturational steroid-induced meiotic G2–M1 transition in zebrafish oocytes

Zygote ◽  
2017 ◽  
Vol 26 (1) ◽  
pp. 62-75 ◽  
Author(s):  
Debabrata Das ◽  
Poulomi Nath ◽  
Soumojit Pal ◽  
Sudip Hajra ◽  
Pritha Ghosh ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Relative Importance ◽  
Phosphatidylinositol 3 Kinase ◽  
Kinase Activation ◽  
Erk Activation ◽  
Mapk Signalling ◽  
Mitogen Activated Protein ◽  
Phosphatidylinositol 3

SummaryParticipation and relative importance of phosphatidylinositol-3 kinase (PI3K) and mitogen-activated protein kinase (MAPK) signalling, either alone or in combination, have been investigated during 17α,20β-dihydroxy-4-pregnen-3-one (DHP)-induced meiotic G2−M1 transition in denuded zebrafish oocyte. Results demonstrate that concomitant with rapid phosphorylation (activation) of Akt (Ser473) and MAPK (ERK1/2) at as early as 15 min of incubation, DHP stimulation promotes enhanced an GVBD response and histone H1 kinase activation between 1 and 5 h in full-grown oocytes in vitro. While p-Akt reaches its peak at 60 to 90 min and undergoes downregulation to the basal level by 240 min, ERK1/2 phosphorylation (activation) increases gradually until 120 min and remains high thereafter. Although, priming with MEK1/2 inhibitor U0126 is without effect, PI3K inhibitors, wortmannin or LY294002, delay the GVBD response significantly (P < 0.001) until 3 h but not at 5 h of incubation. Interestingly, blocking PI3K and MEK function together could abrogate steroid-induced oocyte maturation at all time points tested. While DHP stimulation promotes phospho-PKA catalytic (p-PKAc) dephosphorylation (inactivation) between 30–120 min of incubation, simultaneous inhibition of PI3K and MEK1/2 kinases abrogates DHP action. Conversely, elevated intra-oocyte cAMP, through priming with either adenylyl cyclase (AC) activator forskolin (FK) or dibutyryl cAMP (db-cAMP), abrogates steroid-induced Akt and ERK1/2 phosphorylation. Taken together, these results suggest that DHP-induced Akt and ERK activation precedes the onset of meiosis (GVBD response) in a cAMP-sensitive manner and PI3K/Akt and MEK/MAPK pathways together have a pivotal influence in the downregulation of PKA and resumption of meiotic maturation in zebrafish oocytes in vitro.

scholarly journals SIP/SHIP inhibits Xenopus oocyte maturation induced by insulin and phosphatidylinositol 3-kinase.

1997 ◽  
Vol 17 (5) ◽  
pp. 2559-2565 ◽  
Author(s):  
M Deuter-Reinhard ◽  
G Apell ◽  
D Pot ◽  
A Klippel ◽  
L T Williams ◽  
...  
Keyword(s):  
Xenopus Oocytes ◽  
Germinal Vesicle ◽  
Sh2 Domain ◽  
Mitogen Activated Protein Kinase ◽  
Phosphatidylinositol 3 Kinase ◽  
Germinal Vesicle Breakdown ◽  
Inositol Phosphatase ◽  
Phosphatidylinositol 3

SIP (signaling inositol phosphatase) or SHIP (SH2-containing inositol phosphatase) is a recently identified SH2 domain-containing protein which has been implicated as an important signaling molecule. SIP/SHIP becomes tyrosine phosphorylated and binds the phosphotyrosine-binding domain of SHC in response to activation of hematopoietic cells. The signaling pathways and biological responses that may be regulated by SIP have not been demonstrated. SIP is a phosphatidylinositol- and inositol-polyphosphate 5-phosphatase with specificity in vitro for substrates phosphorylated at the 3' position. Phosphatidylinositol 3'-kinase (PI 3-kinase) is an enzyme which is involved in mitogenic signaling and whose phosphorylated lipid products are predicted to be substrates for SIP. We tested the hypothesis that SIP can modulate signaling by PI 3-kinase in vivo by injecting SIP cRNAs into Xenopus oocytes. SIP inhibited germinal vesicle breakdown (GVBD) induced by expression of a constitutively activated form of PI 3-kinase (p110*) and blocked GVBD induced by insulin. SIP had no effect on progesterone-induced GVBD. Catalytically inactive SIP had little effect on insulin- or PI 3-kinase-induced GVBD. Expression of SIP, but not catalytically inactive SIP, also blocked insulin-induced mitogen-activated protein kinase phosphorylation in oocytes. SIP specifically and markedly reduced the level of phosphatidylinositol (3,4,5) triphosphate [PtdIns(3,4,5)P3] generated in oocytes in response to insulin. These results demonstrate that a member of the phosphatidylinositol polyphosphate 5-phosphatase family can inhibit signaling in vivo. Further, our data suggest that the generation of PtdIns(3,4,5)P3 by PI 3-kinase is necessary for insulin-induced GVBD in Xenopus oocytes.

Gallic acid promotes the in vitro development of sheep secondary isolated follicles involving the phosphatidylinositol 3-kinase pathway

2021 ◽  
pp. 106767
Author(s):  
Gizele A.L. Silva ◽  
Luana B. Araújo ◽  
Larissa C.R. Silva ◽  
Bruna B. Gouveia ◽  
Ricássio S. Barberino ◽  
...  
Keyword(s):  
Gallic Acid ◽  
Phosphatidylinositol 3 Kinase ◽  
In Vitro Development ◽  
Vitro Development ◽  
Kinase Pathway ◽  
Phosphatidylinositol 3

scholarly journals Suppressive Role of Bam32/DAPP1 in Chemokine-Induced Neutrophil Recruitment

2021 ◽  
Vol 22 (4) ◽  
pp. 1825
Author(s):  
Li Hao ◽  
Aaron J. Marshall ◽  
Lixin Liu
Keyword(s):  
Small Gtpases ◽  
Neutrophil Recruitment ◽  
Neutrophil Chemotaxis ◽  
Wild Type ◽  
Adaptor Molecule ◽  
Geranylgeranyltransferase I ◽  
And Migration ◽  
Rap1 Activation

Bam32 (B cell adaptor molecule of 32 kDa) functions in the immune responses of various leukocytes. However, the role of neutrophil Bam32 in inflammation is entirely unknown. Here, we determined the role of Bam32 in chemokine CXCL2-induced neutrophil chemotaxis in three mouse models of neutrophil recruitment. By using intravital microscopy in the mouse cremaster muscle, we found that transmigrated neutrophil number, neutrophil chemotaxis velocity, and total neutrophil chemotaxis distance were increased in Bam32−/− mice when compared with wild-type (WT) mice. In CXCL2-induced mouse peritonitis, the total emigrated neutrophils were increased in Bam32−/− mice at 2 but not 4 h. The CXCL2-induced chemotaxis distance and migration velocity of isolated Bam32−/− neutrophils in vitro were increased. We examined the activation of small GTPases Rac1, Rac2, and Rap1; the levels of phospho-Akt2 and total Akt2; and their crosstalk with Bam32 in neutrophils. The deficiency of Bam32 suppressed Rap1 activation without changing the activation of Rac1 and Rac2. The pharmacological inhibition of Rap1 by geranylgeranyltransferase I inhibitor (GGTI298) increased WT neutrophil chemotaxis. In addition, the deficiency of Bam32, as well as the inhibition of Rap1 activation, increased the levels of CXCL2-induced Akt1/2 phosphorylation at Thr308/309 in neutrophils. The inhibition of Akt by SH-5 attenuated CXCL2-induced adhesion and emigration in Bam32−/− mice. Together, our results reveal that Bam32 has a suppressive role in chemokine-induced neutrophil chemotaxis by regulating Rap1 activation and that this role of Bam32 in chemokine-induced neutrophil recruitment relies on the activation of PI3K effector Akt.

scholarly journals In Vitro Antimetastatic Effect of Phosphatidylinositol 3-Kinase Inhibitor ZSTK474 on Prostate Cancer PC3 Cells

2013 ◽  
Vol 14 (7) ◽  
pp. 13577-13591 ◽  
Author(s):  
Wennan Zhao ◽  
Wenzhi Guo ◽  
Qianxiang Zhou ◽  
Sheng-Nan Ma ◽  
Ran Wang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Kinase Inhibitor ◽  
Phosphatidylinositol 3 Kinase ◽  
Antimetastatic Effect ◽  
Pc3 Cells ◽  
Phosphatidylinositol 3

Phosphatidylinositol 3-kinase activation is mediated by high-affinity interactions between distinct domains within the p110 and p85 subunits

1994 ◽  
Vol 14 (1) ◽  
pp. 42-49
Author(s):  
K H Holt ◽  
L Olson ◽  
W S Moye-Rowley ◽  
J E Pessin
Keyword(s):  
Gene Fusion ◽  
Kinase Activity ◽  
Expression System ◽  
Sh2 Domain ◽  
Full Length ◽  
Transactivation Domain ◽  
Phosphatidylinositol 3 Kinase ◽  
Sh2 Domains ◽  
Amino Terminal ◽  
Phosphatidylinositol 3

Domains of interaction between the p85 and p110 subunits of phosphatidylinositol 3-kinase (PI 3-kinase) were studied with the yeast two-hybrid expression system. A gene fusion between the GAL4 transactivation domain and p85 activated transcription from a GAL1-lacZ reporter gene when complemented with a gene fusion between the GAL4 DNA binding domain and p110. To define subdomains responsible for this interaction, a series of p85 deletion mutants were analyzed. A 192-amino-acid inter-SH2 (IS) fragment (residues 429 to 621) was the smallest determinant identified that specifically associated with p110. In analogous experiments, the subdomain within p110 responsible for interaction with p85 was localized to an EcoRI fragment encoding the amino-terminal 127 residues. Expression of these two subdomains [p85(IS) with p110RI] resulted in 100-fold greater reporter activity than that obtained with full-length p85 and p110. Although the p85(IS) domain conferred a strong interaction with the p110 catalytic subunit, this region was not sufficient to impart phosphotyrosine peptide stimulation of PI 3-kinase activity. In contrast, coexpression of the p110 subunit with full-length p85 or with constructs containing the IS sequences flanked by both SH2 domains of p85 [p85(n/cSH2)] or either of the individual SH2 domains [p85(nSH2+IS) or p85(IS+cSH2)] resulted in PI 3-kinase activity that was activated by a phosphotyrosine peptide. These data suggest that phosphotyrosine peptide binding to either SH2 domain generates an intramolecular signal propagated through the IS region to allosterically activate p110.

scholarly journals Dominant missense mutations in a novel yeast protein related to mammalian phosphatidylinositol 3-kinase and VPS34 abrogate rapamycin cytotoxicity.

1993 ◽  
Vol 13 (10) ◽  
pp. 6012-6023 ◽  
Author(s):  
R Cafferkey ◽  
P R Young ◽  
M M McLaughlin ◽  
D J Bergsma ◽  
Y Koltin ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Dna Sequence ◽  
Leucine Zipper ◽  
Sequence Similarity ◽  
Missense Mutations ◽  
Wild Type ◽  
Phosphatidylinositol 3 Kinase ◽  
Haploid Strain ◽  
Diploid Cells ◽  
Phosphatidylinositol 3

Rapamycin is a macrolide antifungal agent that exhibits potent immunosuppressive properties. In Saccharomyces cerevisiae, rapamycin sensitivity is mediated by a specific cytoplasmic receptor which is a homolog of human FKBP12 (hFKBP12). Deletion of the gene for yeast FKBP12 (RBP1) results in recessive drug resistance, and expression of hFKBP12 restores rapamycin sensitivity. These data support the idea that FKBP12 and rapamycin form a toxic complex that corrupts the function of other cellular proteins. To identify such proteins, we isolated dominant rapamycin-resistant mutants both in wild-type haploid and diploid cells and in haploid rbp1::URA3 cells engineered to express hFKBP12. Genetic analysis indicated that the dominant mutations are nonallelic to mutations in RBP1 and define two genes, designated DRR1 and DRR2 (for dominant rapamycin resistance). Mutant copies of DRR1 and DRR2 were cloned from genomic YCp50 libraries by their ability to confer drug resistance in wild-type cells. DNA sequence analysis of a mutant drr1 allele revealed a long open reading frame predicting a novel 2470-amino-acid protein with several motifs suggesting an involvement in intracellular signal transduction, including a leucine zipper near the N terminus, two putative DNA-binding sequences, and a domain that exhibits significant sequence similarity to the 110-kDa catalytic subunit of both yeast (VPS34) and bovine phosphatidylinositol 3-kinases. Genomic disruption of DRR1 in a mutant haploid strain restored drug sensitivity and demonstrated that the gene encodes a nonessential function. DNA sequence comparison of seven independent drr1dom alleles identified single base pair substitutions in the same codon within the phosphatidylinositol 3-kinase domain, resulting in a change of Ser-1972 to Arg or Asn. We conclude either that DRR1 (alone or in combination with DRR2) acts as a target of FKBP12-rapamycin complexes or that a missense mutation in DRR1 allows it to compensate for the function of the normal drug target.

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