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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The indispensability of arginine has not been conclusively established in newborns. Because parenteral feeding bypasses the gut (where de novo synthesis of arginine occurs from proline), a dietary supply of arginine that is sufficient to maintain
urea
cycle function may be of greater importance during intravenous compared with enteral feeding. Two-day-old piglets (n = 12) were fed nutritionally complete diets for 5 days via either a central vein catheter (IV pigs, n = 6) or a gastric catheter (IG pigs, n = 6). Subsequently, each piglet received three incomplete test diets [arginine free (-
ARG
/+PRO), proline free (-PRO/+ARG), or arginine and proline free (-
ARG
/-PRO)] in a randomized crossover design. Plasma ammonia was assayed every 30 min for 8 h or until hyperammonemia was observed. Ammonia increased rapidly in IV pigs receiving -
ARG
/+PRO and -
ARG
/-PRO (84 +/- 36 and 74 +/- 37 micromol. l(-1). h(-1), respectively), requiring early diet cessation. A rapid increase was also exhibited by IG pigs receiving the -
ARG
/-PRO, but not the -
ARG
/+PRO diet (31 +/- 15 vs. 11 +/- 7 micromol. l(-1). h(-1), respectively, P < 0.05). Plasma arginine and proline were indicative of deficiency (IG and IV groups) when deplete diets were infused. Arginine is indispensable in parenteral and enteral nutrition, independent of dietary proline.
...
PMID:Proline ameliorates arginine deficiency during enteral but not parenteral feeding in neonatal piglets. 1044 16
The small GTPases of the Rho family are intimately involved in integrin-mediated changes in the actin cytoskeleton that accompany cell spreading and motility. The exact means by which the Rho family members elicit these changes is unclear. Here, we demonstrate that the interaction of paxillin via its LD4 motif with the putative
ARF
-GAP paxillin kinase linker (PKL) (Turner et al., 1999), is critically involved in the regulation of Rac-dependent changes in the actin cytoskeleton that accompany cell spreading and motility. Overexpression of a paxillin LD4 deletion mutant (paxillinDeltaLD4) in CHO.K1 fibroblasts caused the generation of multiple broad lamellipodia. These morphological changes were accompanied by an increase in cell protrusiveness and random motility, which correlated with prolonged activation of Rac. In contrast, directional motility was inhibited. These alterations in morphology and motility were dependent on a paxillin-PKL interaction. In cells overexpressing paxillinDeltaLD4 mutants, PKL localization to focal contacts was disrupted, whereas that of
focal adhesion kinase
(
FAK
) and vinculin was not. In addition,
FAK
activity during spreading was not compromised by deletion of the paxillin LD4 motif. Furthermore, overexpression of PKL mutants lacking the paxillin-binding site (PKLDeltaPBS2) induced phenotypic changes reminiscent of paxillinDeltaLD4 mutant cells. These data suggest that the paxillin association with PKL is essential for normal integrin-mediated cell spreading, and locomotion and that this interaction is necessary for the regulation of Rac activity during these events.
...
PMID:The LD4 motif of paxillin regulates cell spreading and motility through an interaction with paxillin kinase linker (PKL). 1144 98
Increased expression of
focal adhesion kinase
(
FAK
) was consistently observed in low- and high-grade astrocytomas and during glioblastoma progression after radiotherapy, but not in the more benign oligodendroglioma. In glioblastoma cell lines deficient for p53, p16(INK4A), and p14(
ARF
),
FAK
was inhibited in a dominant-negative manner by the focal adhesion targeting (FAT) domain, reducing invasion. In addition, caspase-3 activity was increased after serum withdrawal, or by cisplatin in the presence of serum, or upon loss of substrate attachment, and was in each case independent of PTEN status. Our results identify
FAK
as a potential target for anti-invasive strategies against infiltrating glioma cells.
...
PMID:PTEN-independent induction of caspase-mediated cell death and reduced invasion by the focal adhesion targeting domain (FAT) in human astrocytic brain tumors which highly express focal adhesion kinase (FAK). 1147 98
Paxillin is a focal-adhesion associated protein implicated in the regulation of integrin signaling and organization of the actin cytoskeleton. Paxillin associates with numerous signaling molecules including adaptor molecules (p130Cas, CRK), kinases (FAK, Pyk2, PAK and
SRC
), tyrosine phosphatases (PTP-PEST),
ARF
-GAP proteins (p95pkl, PAG3) and papillomavirus E6 oncoproteins. Although paxillin is tyrosine phosphorylated in cellular processes such as cell attachment and spreading, little direct evidence is available about paxillin's role in these events. Targeted gene disruption was used to generate paxillin null mouse embryonic stem (ES) cells and paxillin null differentiated cells. Paxillin null ES cells exhibit delayed spreading on integrin binding substrates fibronectin and laminin, and there is reduced tyrosine phosphorylation of Focal Adhesion Kinase (FAK). Both of these phenotypes are recovered in paxillin knockout cells upon exogenous re-expression of paxillin. The individual LD motifs of paxillin that are binding sites for FAK, vinculin and
ARF
-GAP proteins, as well as tyrosine residues that when phosphorylated create binding sites for CRK family members, are dispensable for FAK phosphorylation and early cell spreading. These results demonstrate that paxillin contributes to attachment-dependent tyrosine phosphorylation of FAK and early cell spreading in ES cells.
...
PMID:Paxillin null embryonic stem cells are impaired in cell spreading and tyrosine phosphorylation of focal adhesion kinase. 1179 Nov 80
ASAP1 (ADP ribosylation factor [
ARF
]- GTPase-activating protein [GAP] containing SH3, ANK repeats, and PH domain) is a phospholipid-dependent
ARF
-GAP that binds to and is phosphorylated by pp60(Src). Using affinity chromatography and yeast two-hybrid interaction screens, we identified ASAP1 as a major binding partner of protein tyrosine kinase
focal adhesion kinase
(
FAK
). Glutathione S-transferase pull-down and coimmunoprecipitation assays showed the binding of ASAP1 to
FAK
is mediated by an interaction between the C-terminal SH3 domain of ASAP1 with the second proline-rich motif in the C-terminal region of
FAK
. Transient overexpression of wild-type ASAP1 significantly retarded the spreading of REF52 cells plated on fibronectin. In contrast, overexpression of a truncated variant of ASAP1 that failed to bind
FAK
or a catalytically inactive variant of ASAP1 lacking GAP activity resulted in a less pronounced inhibition of cell spreading. Transient overexpression of wild-type ASAP1 prevented the efficient organization of paxillin and
FAK
in focal adhesions during cell spreading, while failing to significantly alter vinculin localization and organization. We conclude from these studies that modulation of
ARF
activity by ASAP1 is important for the regulation of focal adhesion assembly and/or organization by influencing the mechanisms responsible for the recruitment and organization of selected focal adhesion proteins such as paxillin and
FAK
.
...
PMID:The association of ASAP1, an ADP ribosylation factor-GTPase activating protein, with focal adhesion kinase contributes to the process of focal adhesion assembly. 1205 76
We evaluated the analytical performance of the i-STAT Portable Clinical Analyzer (PCA), a point-of-care testing system consisting of a hand-held analyzer and single-use cartridges that measure different panels of electrolytes, metabolites, blood gases, and hematocrit in 65-100 microl of blood. Our objective was to determine whether PCA measurements at the bedside of patients in the neonatal and pediatric intensive care units of the MUSC Children's Hospital would be as reliable as those performed by the clinical laboratory's primary methods (Radiometer
ABL
725 blood gas analyzer; Vitros 750 chemistry analyzer; and Coulter STKS hematology analyzer). Four cartridge types: (a) EC8+ (sodium; potassium; chloride;
urea
; glucose; pH; blood gases [PO2; pCO2]), (b) EC6+ (sodium; potassium; ionized calcium; glucose; hematocrit; pH), (c) G3+ (pH; PO2; pCO2), and (d) creatinine, were assessed for reproducibility, linearity, and method comparisons using aqueous samples, blood samples supplemented with several analytes, and -225 blood samples from patients. Reproducibility (CV) was good (< 2%) for electrolytes, glucose,
urea
, and pH, satisfactory (< 6.5%) for blood gases and creatinine, but poor (21%) for hematocrit. Linearity concentrations spanning the clinically relevant ranges were verified for all analytes. Method comparison studies with samples separated into 2 subgroups by patient age (> or < 3 mo) showed that agreement between the PCA and the primary methods was clinically acceptable. After the PCA was implemented for clinical testing, the observation of discrepant results of creatinine concentrations in neonatal blood samples that would have affected clinical management led to a second creatinine comparison study (59 additional samples) and to our eventual discontinuation of the PCA creatinine assay. This problem notwithstanding, the successful implementation of the PCA is attributed to careful analytical evaluations and ongoing communication with the clinical staff.
...
PMID:Evaluation of the i-STAT Portable Clinical Analyzer for point-of-care blood testing in the intensive care units of a university children's hospital. 1217 85
Leupaxin is a cytoskeleton adaptor protein that was first identified in human macrophages and was found to share homology with the focal adhesion protein, paxillin. Leupaxin possesses several protein-binding domains that have been implicated in targeting proteins such as
focal adhesion kinase
(pp125FAK) to focal adhesions. Leupaxin can be detected in monocytes and osteoclasts, both cells of hematopoietic origin. We have identified leupaxin to be a component of the osteoclast podosomal signaling complex. We have found that leupaxin in murine osteoclasts is associated with both
PYK2
and pp125FAK in the osteoclast. Treatment of osteoclasts with TNF-alpha and soluble osteopontin were found to stimulate tyrosine phosphorylation of both leupaxin and leupaxin-associated
PYK2
. Leupaxin was found to co-immunoprecipitate with the protein tyrosine phosphatase PTP-PEST. The cellular distribution of leupaxin,
PYK2
, and protein tyrosine phosphorylation-PEST co-localized at or near the osteoclast podosomal complex. Leupaxin was also found to associate with the
ARF
-GTPase-activating protein, paxillin kinase linker p95PKL, thereby providing a link to regulators of cytoskeletal dynamics in the osteoclast. Overexpression of leupaxin by transduction into osteoclasts evoked numerous cytoplasmic projections at the leading edge of the cell, resembling a motile phenotype. Finally, in vitro inhibition of leupaxin expression in the osteoclast led to a decrease in resorptive capacity. Our data suggest that leupaxin may be a critical nucleating component of the osteoclast podosomal signaling complex.
...
PMID:Leupaxin is a critical adaptor protein in the adhesion zone of the osteoclast. 1267 28
Human malignant gliomas arise from neural progenitor cells and/or dedifferentiated astrocytes. By now, they are genetically so well characterized that several murine glioma models have emerged that faithfully reiterate the typical histological features of the disease. In experimental animals, only one or two elements of the growth factor/Ras, PI3K/PTEN/
PKB
, p53/
ARF
/HDM2, and p16/Rb/cyclinD/CDK4 pathways are targeted. In human gliomas, many additional genes and pathways are targeted due to a most severe mutator phenotype that leads to the accumulation of countless epigenetic and genetic alterations. Changes that convey a growth advantage are selected for, leading to overgrowth of precursor cell populations with increasingly malignant tumor cell clones. While murine models represent a powerful tool for elucidating the role of genetic pathways, mechanisms of response and resistance to new therapeutic agents might be fundamentally different due to the high degree of genomic instability in the human disease. In fact, little is known about the molecular causes of genomic instability involved in gliomas, except for the rare Turcot's syndrome, O(6)-methylguanine-DNA methyltransferase, and the apurinic/apyrimidinic endonuclease Ape-1. Novel approaches that selectively exploit fundamental metabolic differences between tumor and normal cells have to consider these fundamental differences between human disease and presently available, highly sophisticated animal models.
...
PMID:Genes and pathways driving glioblastomas in humans and murine disease models. 1278 72
Antibodies of type IgG may be divided into two classes, called lambda or kappa, depending on the type of light chain. We have identified a conserved pocket between the two domains CH1 and CL of human IgG kappa-Fab, which is not present in the lambda type. This pocket was used as a target docking site with the purpose of exploring the possibilities of designing affinity ligands that could function as such even after immobilization to gel. The idea of the design arose mainly from the results of the saturated transfer difference (
STD
-NMR) screening of 46 compounds identified by means of virtual docking of 60 K diverse compounds from the Available Chemicals Directory (ACD). Surface plasmon resonance (SPR) was used as an alternative method to monitor binding in solution. A total of 24 compounds belonging to a directed library were designed, synthesized, and screened in solution. They consist essentially of an amino acid condensed to a N,N'-methylated phenyl
urea
.
STD
-NMR results suggest that a small hydrophobic side chain in the condensed amino acid promotes binding, whereas a hydroxyl-group-containing side chain implies absence of
STD
-NMR signals. Three compounds of the directed library were immobilized and evaluated as chromatographic probes. In one case, using D-Pro as the condensed amino acid, columns packed with ligand-coupled Sepharose (Amersham Biosciences) retained two different monoclonal samples of kappa-Fab fragments with different variable regions, whereas a sample of monoclonal lambda-Fab fragments was not retained under similar chromatographic conditions.
...
PMID:A novel and conserved pocket of human kappa-Fab fragments: design, synthesis, and verification of directed affinity ligands. 1515 83
The non-ionized form of ammonia is very toxic to many aquatic species. It is especially important in several aspects of fish biology. A large range of organismal strategies for coping with environmental stressors is usually observed in living organisms. Among those, the responses for managing chemical stressors are well studied. The present work compares biochemical responses of two evolutionarily close species, Hoplias malabaricus and Hoplerythrinus unitaeniatus, exposed to environmental ammonia. Adult fish were submitted to 1.0 mg/L of ammonium chloride for 24 hours, and plasma ammonia and
urea
levels were determined. The activities of OUC enzymes OCT and
ARG
, and the accessory enzyme GS, were quantified in liver extract and are expressed below in mumol/min/mg of wet tissue. Increases in OUC enzymes (GS from 1.14 to 2.43, OCT from 0.81 to 1.72, and
ARG
from 3.15 to 4.23), plasma ammonia (from 0.95 to 1.42 mmol/L), and plasma
urea
(from 0.82 to 1.53 mmol/L) were observed (p < 0.05) in H. malabaricus exposed to 1 mg/L of ammonia chloride. The GS in H. unitaeniatus increased from 1.43 to 1.84, however the OCT,
ARG
, and plasma
urea
from H. unitaeniatus did not change. These data indicate that each species responds differently to the same environmental stressor.
...
PMID:Biochemical responses of two erythrinidae fish to environmental ammonia. 1519 68
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