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2.
Burns ; 42(2): 414-20, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26775217

ABSTRACT

Parents of children with burns experience a range of psychological reactions and symptoms, and parents' health is known to impact children's health. So far, there is little research into potential mechanisms that maintain parents' symptoms. The aim was to investigate parental injury-related fear-avoidance, and its associations with injury severity and health measures. Parents (n=107) of children aged 0.4-18 years that sustained burns 0.1-9.0 years previously completed questionnaires on fear-avoidance, posttraumatic stress, and health of the child. Analyses showed that the average level of fear-avoidance was low and positively associated with measures of injury severity and parents' symptoms of posttraumatic stress, and negatively associated with parents' ratings of their child's health. In two separate multiple regressions with parents' symptoms of PTSD and the child's health as dependent variables, fear-avoidance made the largest contribution in both models while injury severity was non-significant. Results were not related to comorbid conditions of the child, scarring, or parent-related socio-demographic variables. In summary, injury-related fear-avoidance is more likely among parents whose children sustain more severe burns. In turn, fear-avoidance contributes significantly to parents' symptoms of PTSD and to poorer health ratings regarding the child, irrespective of injury severity or child comorbidity.


Subject(s)
Avoidance Learning , Burns/psychology , Fear/psychology , Parents/psychology , Stress Disorders, Post-Traumatic/psychology , Adolescent , Child , Child, Preschool , Female , Health Status , Humans , Infant , Linear Models , Male , Surveys and Questionnaires , Trauma Severity Indices
3.
Gen Hosp Psychiatry ; 38: 105-8, 2016.
Article in English | MEDLINE | ID: mdl-26596191

ABSTRACT

OBJECTIVE: Children sustaining burns that require treatment in a burn center have a need for multiprofessional aftercare services over a prolonged time. So far, there is little research into satisfaction with care and support after pediatric burns. The aim was to investigate parents' perception of support after pediatric burn and associations with parent, child and injury characteristics. METHOD: Parents (n=101) of children aged 0.4-17.8 years completed questionnaires on support, parent's psychological symptoms and health of the child. Time since injury was 0.1-9.0 years. RESULTS: Perceived lack of psychosocial, medical, societal or family support was reported by 21% of the parents. Lack of support was not associated with injury or sociodemographic characteristics, but it was significantly associated with parents' symptoms of general anxiety, depression and injury-related fear avoidance, as well as parents' ratings of their child's general health and heat sensitivity. CONCLUSION: Perceived support did not differ on account of burn severity or sociodemographic status. However, care providers should be more attentive to and supportive of parents signaling poorer general health in their child and cognitive beliefs that the child is at risk for harm when active and parents who themselves show signs of psychological symptoms.


Subject(s)
Burns/rehabilitation , Health Services Needs and Demand , Parents/psychology , Social Support , Stress Disorders, Post-Traumatic/psychology , Adolescent , Aftercare , Anxiety/psychology , Burn Units , Burns/psychology , Child , Child, Preschool , Depression/psychology , Female , Humans , Infant , Male , Patient Satisfaction , Perception , Surveys and Questionnaires , Trauma Severity Indices
4.
Burns ; 39(2): 229-35, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23318216

ABSTRACT

BACKGROUND: Health-related quality of life (HRQoL) is reduced after a burn, and is affected by coexisting conditions. The aims of the investigation were to examine and describe effects of coexisting disease on HRQoL, and to quantify the proportion of burned people whose HRQoL was below that of a reference group matched for age, gender, and coexisting conditions. METHOD: A nationwide study covering 9 years and examined HRQoL 12 and 24 months after the burn with the SF-36 questionnaire. The reference group was from the referral area of one of the hospitals. RESULTS: The HRQoL of the burned patients was below that of the reference group mainly in the mental dimensions, and only single patients were affected in the physical dimensions. The factor that significantly affected most HRQoL dimensions (n=6) after the burn was unemployment, whereas only smaller effects could be attributed directly to the burn. CONCLUSION: Poor HRQoL was recorded for only a small number of patients, and the decline were mostly in the mental dimensions when compared with a group adjusted for age, gender, and coexisting conditions. Factors other than the burn itself, such as mainly unemployment and pre-existing disease, were most important for the long term HRQoL experience in these patients.


Subject(s)
Burns/psychology , Health Status , Quality of Life , Adolescent , Adult , Aged , Aged, 80 and over , Burns/complications , Burns/physiopathology , Female , Humans , Injury Severity Score , Longitudinal Studies , Male , Middle Aged , Prospective Studies , Social Adjustment , Surveys and Questionnaires , Young Adult
5.
Burns ; 35(2): 194-200, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19070969

ABSTRACT

The aim of this prospective study was to find predictors of patient satisfaction with burn care. Sixty-nine consecutive adult patients undergoing acute treatment in a Burn Unit completed the following questionnaires: the Swedish universities Scales of Personality, the Impact of Event Scale-Revised, and the Hospital Anxiety and Depression Scale. Socio-demographic data and burn severity were registered. One year later they completed the Patient Satisfaction-Results and Quality (PS-RESKVA) questionnaire containing four subscales: quality of contact with nursing staff (QCN), quality of contact with medical staff (QCM), adequate treatment information (INF), and global satisfaction with treatment (GS). Each subscale was treated as a dependent variable in separate multiple regression models. Overall, the explained variance was low to moderate (range adjusted R(2)=0.06-0.19). Variables remaining in the models were: intrusive symptoms, and the personality trait stress susceptibility for QCN; age, education, and symptoms of hyperarousal for QCM; trait irritability for INF; and age and the personality traits detachment and social desirability for GS. In conclusion, psychological and socio-demographic variables predicted satisfaction to some degree, whereas injury severity did not. The low amount of explained variance suggests that other factors, hypothetically related to care itself, determine patient satisfaction as assessed by the PS-RESKVA.


Subject(s)
Burns/therapy , Patient Satisfaction/statistics & numerical data , Adult , Aged , Aged, 80 and over , Burn Units/standards , Burns/psychology , Female , Humans , Male , Middle Aged , Professional-Patient Relations , Prospective Studies , Surveys and Questionnaires , Treatment Outcome , Young Adult
6.
Burns ; 34(6): 783-90, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18378086

ABSTRACT

Patient satisfaction is an important outcome in health care but has not been studied in relation to burn care. The aim was to explore factors related to satisfaction with care 1-6 years after a burn. Participants were 86 adult burn patients, injured on average 3.6 years previously. The Patient Satisfaction-Results and Quality (PS-RESKVA) was used to assess satisfaction. It has four subscales: Quality of contact with the nursing staff (QCN), Quality of contact with the medical staff (QCM), Adequate treatment information (INF) and Global satisfaction with treatment (GS). Further, data were gathered regarding personality traits and health. Average scores for QCN were significantly higher than scores for the other subscales, and INF received the lowest mean score. In multiple regressions, the PS-RESKVA subscales were associated with better interpersonal relationships (all PS-RESKVA subscales), more sensation seeking (QCM, INF, and GS) and less aggressiveness (QCM and GS). Other variables contributed to a lesser degree. Total amount of explained variance ranged between 18% and 25% for the PS-RESKVA subscales. In summary, satisfaction with burn care was only moderately explained by health and personality characteristics. Further, former patients rated satisfaction with nursing staff higher than other aspects of care, especially information routines.


Subject(s)
Burns/psychology , Outcome Assessment, Health Care/standards , Patient Satisfaction , Quality of Health Care/standards , Adolescent , Adult , Aged , Aged, 80 and over , Burns/nursing , Burns/therapy , Female , Follow-Up Studies , Humans , Injury Severity Score , Male , Middle Aged , Pain/nursing , Pain/psychology , Pain Management , Physician-Patient Relations , Quality of Health Care/trends , Retrospective Studies , Sickness Impact Profile , Surveys and Questionnaires
7.
Burns ; 32(4): 408-15, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16621317

ABSTRACT

Dysfunctional beliefs such as fear-avoidance (i.e. fear of re-injury) and personality traits such as neuroticism are risk factors for poor health. However, there is little information regarding associations with poor perceived health after severe burn and what level of fear-avoidance is associated with poor health. In this study, we investigated fear-avoidance and neuroticism regarding their associations with post-burn health. Participants were 86 recovered burn patients and data were collected by a postal survey. Post-burn health was assessed with the nine subscales of the Burn Specific Health Scale-Brief (BSHS-B). In logistic regressions, fear-avoidance was related to poorer health in six subscales assessing both physical and psychosocial problems. Neuroticism was associated with poorer health in three subscales assessing mainly psychosocial problems. Chi-square analyses showed that participants with a moderate or high level of fear-avoidance >or=1.0 (out of 4) were more likely to describe their health as poor and had a longer sick leave than those with a fear-avoidance level of <1.0. In summary, fear-avoidance was associated with poorer health even at moderate levels and was associated with several aspects of post-burn health.


Subject(s)
Avoidance Learning , Burns/psychology , Fear , Neurotic Disorders/etiology , Adolescent , Adult , Aged , Aged, 80 and over , Female , Health Status , Humans , Logistic Models , Male , Middle Aged , Socioeconomic Factors
8.
Disabil Rehabil ; 27(15): 863-70, 2005 Aug 05.
Article in English | MEDLINE | ID: mdl-16096238

ABSTRACT

PURPOSE: The aim of the study was to evaluate which factors are associated with the use of healthcare a long time after severe burn injury. METHOD: After a review process based on clinical reasoning, 69 former burn patients out of a consecutive group treated at the Uppsala Burn Unit from 1980--1995 were visited in their homes and their use of care and support was assessed in a semi-structured interview. Post-burn health was assessed with the Burn-Specific Health Scale-Brief (BSHS-B) and personality was assessed with the Swedish universities Scales of Personality (SSP). RESULTS: The participants were injured on average eight years previously. Thirty-four had current contact with healthcare due to their burn injury and had significantly lower scores on three BSHS-B-domains: Simple Abilities, Work and Hand function, and significantly higher scores for the SSP-domain Neuroticism and the SSP-scales Stress Susceptibility, Lack of Assertiveness, and lower scores for Social Desirability. There was no relation to age, gender, time since injury, length of stay, or to the surface area burned. CONCLUSIONS: A routine screening of personality traits as a supplement to long-term follow-ups may help in identifying the patient's need for care.


Subject(s)
Attitude to Health , Burns/psychology , Health Status Indicators , Personality Assessment , Adult , Burns/rehabilitation , Female , Follow-Up Studies , Humans , Life Change Events , Male , Middle Aged , Needs Assessment , Surveys and Questionnaires , Sweden , Time Factors
9.
Burns ; 28(6): 549-54, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12220912

ABSTRACT

The aim of this study was to investigate coping patterns, health status and personality traits in burned adults. Subjects were 161 burn patients treated at the Uppsala University Hospital between 1980 and 1995. Measures were the coping with burns questionnaire (CBQ), the burn specific health scale-brief (BSHS-B) and the Swedish universities scales of personality (SSP). The CBQ was subjected to a K-means cluster analysis and three clusters were derived: extensive, adaptive, and avoidant copers. Extensive copers used the most coping and took an intermediate role regarding health status and the personality trait of neuroticism. Adaptive copers preferred the strategies emotional support and optimism/problem solving, and had the highest health status ratings. Avoidant copers preferred the strategy avoidance and reported the lowest use of emotional support and optimism/problem solving. They had the lowest health status ratings and the highest ratings on neuroticism and aggressiveness. The clusters did not differ in severity of injury or time since injury. In conclusion, coping patterns can be discerned among burn patients, and those individuals preferring avoidance and lacking other coping options displayed more maladaptive traits and poorer health status years after the burn.


Subject(s)
Adaptation, Psychological , Burns/psychology , Adult , Cluster Analysis , Female , Health Status Indicators , Humans , Male , Personality , Self-Assessment , Surveys and Questionnaires
10.
Cell Signal ; 10(6): 407-13, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9720763

ABSTRACT

Activation of the mitogen-activated protein kinase (MAPK) pathway by the T-cell antigen receptor (TCR) in T cells involves a positive role for phosphatidylinositol 3-kinase (PI3K) activity. We recently reported that over-expression of the Syk protein tyrosine kinase in the Lck-negative JCaM1 cells enabled the TCR to induce a normal activation of the Erk2 MAPK and enhanced transcription of a reporter gene driven by the nuclear factor of activated T cells and AP-1. Because this system allows us to analyse the targets for Syk in receptor-mediated signalling, we examined the role of PI3K in signalling events between the TCR-regulated Syk and the downstream activation of Erk2. We report that inhibition of PI3K by wortmannin or an inhibitory p85 construct, p85deltaiSH2, reduced the TCR-induced Syk-dependent activation of Erk2, as well as the appearance of phospho-Erk and phospho-Mek. At the same time, expression of Syk resulted in the activation-dependent phosphorylation of three proteins that bound to the src homology 2 (SH2) domains of PI3K p85. The strongest of these bands had an apparent molecular mass of 36-38 kDa on SDS gels, and it was quantitatively removed from the lysates by adsorption to a fusion protein containing the SH2 domain of Grb2. The appearance of this band was Syk dependent, and it was seen only upon triggering of the TCR complex. Thus, p36/38 was phosphorylated by Syk or a Syk-regulated kinase, and this protein may provide a link to the recruitment and activation of PI3K, as well as to the Ras-MAPK pathway, in TCR-triggered T cells.


Subject(s)
Adaptor Proteins, Signal Transducing , Enzyme Precursors/metabolism , MAP Kinase Kinase Kinase 1 , Phosphatidylinositol 3-Kinases/metabolism , Phosphoproteins/metabolism , Protein-Tyrosine Kinases/metabolism , Proteins/metabolism , T-Lymphocytes/metabolism , Androstadienes/pharmacology , CD3 Complex/physiology , Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Cell Line , Enzyme Activation , Enzyme Inhibitors/pharmacology , GRB2 Adaptor Protein , Intracellular Signaling Peptides and Proteins , Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/physiology , Mitogen-Activated Protein Kinase 1 , Molecular Weight , Phosphoinositide-3 Kinase Inhibitors , Phosphoproteins/chemistry , Phosphorylation , Protein Binding , Protein Serine-Threonine Kinases/metabolism , Receptors, Antigen, T-Cell/physiology , Signal Transduction/physiology , Syk Kinase , T-Lymphocytes/enzymology , Wortmannin , src Homology Domains
11.
J Biol Chem ; 273(7): 3994-4000, 1998 Feb 13.
Article in English | MEDLINE | ID: mdl-9461588

ABSTRACT

In cells expressing the oncogenic Bcr-Abl tyrosine kinase, the regulatory p85 subunit of phosphatidylinositol 3-kinase is phosphorylated on tyrosine residues. We report that this phosphorylation event is readily catalyzed by the Abl and Lck protein-tyrosine kinases in vitro, by Bcr-Abl or a catalytically activated Lck-Y505F in co-transfected COS cells, and by endogenous kinases in transfected Jurkat T cells upon triggering of their T cell antigen receptor. Using these systems, we have mapped a major phosphorylation site to Tyr-688 in the C-terminal SH2 domain of p85. Tyrosine phosphorylation of p85 in vitro or in vivo was not associated with detectable change in the enzymatic activity of the phosphatidylinositol 3-kinase heterodimer, but correlated with a strong reduction in the binding of some, but not all, phosphoproteins to the SH2 domains of p85. This provides an additional candidate to the list of SH2 domains regulated by tyrosine phosphorylation and may explain why association of phosphatidylinositol 3-kinase with some cellular ligands is transient or of lower stoichiometry than anticipated.


Subject(s)
Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Tyrosine/metabolism , src Homology Domains/physiology , Fusion Proteins, bcr-abl/metabolism , Gene Expression Regulation, Neoplastic/genetics , Humans , Phosphorylation , Phosphotyrosine/analysis , Transfection/genetics , Tumor Cells, Cultured
12.
Eur J Biochem ; 237(3): 736-42, 1996 May 01.
Article in English | MEDLINE | ID: mdl-8647120

ABSTRACT

Activation of resting T lymphocytes by ligands to the complex of T cell antigen receptor (TCR) and CD3 is initiated by a series of critical tyrosine phosphorylation and dephosphorylation events. Protein-tyrosine kinases of the Syk, Src and Csk families and the CD45 protein-tyrosine phosphatase (PTPase) are known to be involved in these early biochemical reactions. We have found that one of the two T-cell-expressed SH2-domain-containing PTPases, SHPTP2, is rapidly phosphorylated on tyrosine upon addition of anti-CD3 mAbs. This response was absent in cells lacking the Src family kinase Lck. Concomitantly with tyrosine phosphorylation, SHPTP2 co-immunoprecipitated with two unphosphorylated cellular proteins; phosphatidylinositol 3-kinase p85 and Grb2. Binding of SHPTP2 to Grb2 occurred through the SH2 domain of Grb2, while the association between SHPTP2 and p85 seemed to be mediated through Grb2 as an intermediate. In addition, many other molecules associate with Grb2 and may thereby become juxtaposed to SHPTP2. Our results indicate that SHPTP2 participates actively at an early stage in TCR signaling and that its phosphorylation on tyrosine may direct a Grb2-dependent association with selected substrates.


Subject(s)
Adaptor Proteins, Signal Transducing , Lymphocyte Activation/physiology , Protein Tyrosine Phosphatases/immunology , T-Lymphocytes/immunology , Amino Acid Sequence , Binding Sites , CD3 Complex/metabolism , Cell Line , GRB2 Adaptor Protein , Humans , Lymphocyte Specific Protein Tyrosine Kinase p56(lck) , Molecular Sequence Data , Phosphatidylinositol 3-Kinases , Phosphorylation , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Protein Phosphatase 2 , Protein Tyrosine Phosphatases/genetics , Protein Tyrosine Phosphatases/metabolism , Proteins/genetics , Proteins/metabolism , Receptors, Antigen, T-Cell/metabolism , Tyrosine/metabolism , src Homology Domains , src-Family Kinases/metabolism
13.
Eur J Biochem ; 235(3): 828-35, 1996 Feb 01.
Article in English | MEDLINE | ID: mdl-8654435

ABSTRACT

The production of 3-phosphorylated inositol phospholipids is implicated in regulation of cell growth and transformation. To explore the role of these lipids in T cell antigen receptor (TCR)/CD3-induced signaling, we have examined the effects of a specific phosphatidylinositol 3-kinase (PtdIns3K) inhibitor, wortmannin, and overexpression of two PtdIns3K constructs on the activation of down-stream effectors in anti-CD3 treated T cells. We report that treatment of cells with wortmannin blocked anti-CD3-induced activation of the mitogen-activation kinase Erk2 while not affecting phorbol-ester-induced Erk2 activation. An inactive analog of wortmannin, WM12, did not affect TCR/CD3-induced Erk2 activation, and wortmannin had no effect on the activity of Erk2 when added directly to the in vitro assays. Expression of a disruptive PtdIns3K construct also reduced Erk2 activation, while a construct that stimulates PtdIns3K enhanced the activation of Erk2. Receptor-induced activation of other Ser/Thr kinases, such as c-Raf, B-Raf, Mek1, Mek2, Mekk, was not affected by wortmannin. Our results suggest that the production of 3-phosphorylated inositol phospholipids is involved in the activation of Erk2, but does not regulate the enzymes that are thought to be upstream of Erk2.


Subject(s)
CD3 Complex/metabolism , Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Phosphotransferases (Alcohol Group Acceptor)/antagonists & inhibitors , Receptors, Antigen, T-Cell/antagonists & inhibitors , Amino Acid Sequence , Androstadienes/pharmacology , DNA Replication/drug effects , Enzyme Activation , Humans , Mitogen-Activated Protein Kinase 1 , Molecular Sequence Data , Phosphatidylinositol 3-Kinases , Phosphorylation , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Protein Kinases/drug effects , Protein Kinases/metabolism , Signal Transduction , Tumor Cells, Cultured , Tyrosine/metabolism , Wortmannin
14.
Proc Natl Acad Sci U S A ; 92(22): 10142-6, 1995 Oct 24.
Article in English | MEDLINE | ID: mdl-7479742

ABSTRACT

Proteins of the 14-3-3 family can associate with, and/or modulate the activity of, several protooncogene and oncogene products and, thus, are implicated in regulation of signaling pathways. We report that 14-3-3 is associated with another important transducing enzyme, phosphatidylinositol 3-kinase (PI3-K). A recombinant 14-3-3 fusion protein bound several tyrosine-phosphorylated proteins from antigen receptor-stimulated T lymphocytes. PI3-K was identified by immunoblotting and enzymatic assays as one of the 14-3-3-binding proteins in resting or activated cells. Moreover, endogenous 14-3-3 and PI3-K were coimmunoprecipitated from intact T cells. Far-Western blots of gel-purified, immunoprecipitated PI3-K with a recombinant 14-3-3 fusion protein revealed direct binding of 14-3-3 to the catalytic subunit (p110) of PI3-K. Finally, anti-phosphotyrosine immunoprecipitates from activated, 14-3-3-overexpressing cells contained lower PI3-K enzymatic activity than similar immunoprecipitates from control cells. These findings suggest that association of 14-3-3 with PI3-K in hematopoietic (and possibly other) cells regulates the enzymatic activity of PI3-K during receptor-initiated signal transduction.


Subject(s)
Phosphotransferases (Alcohol Group Acceptor)/antagonists & inhibitors , Proteins/metabolism , T-Lymphocytes/metabolism , Tyrosine 3-Monooxygenase , 14-3-3 Proteins , Base Sequence , Blotting, Western , Cell Line , DNA Primers , Enzyme Inhibitors/metabolism , Glutathione Transferase/isolation & purification , Glutathione Transferase/metabolism , Humans , Leukemia, T-Cell , Molecular Sequence Data , Phosphatidylinositol 3-Kinases , Phosphoproteins/isolation & purification , Phosphoproteins/metabolism , Phosphotransferases (Alcohol Group Acceptor)/isolation & purification , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Polymerase Chain Reaction , Proteins/isolation & purification , Recombinant Fusion Proteins/metabolism , Restriction Mapping , T-Lymphocytes/immunology , Tumor Cells, Cultured
15.
Mol Immunol ; 31(17): 1295-302, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7997241

ABSTRACT

The T cell protein tyrosine kinase p56lck is implicated in thymic development and mitogenic activation of T lymphocytes, and is itself regulated by reversible tyrosine phosphorylation. When phenylarsine oxide (PAO), a membrane-permeable inhibitor of phosphotyrosine phosphatases, was added to Jurkat T leukemia or LSTRA thymoma cells, the phosphate content of p56lck increased rapidly. The sites of increased phosphorylation were mapped to Tyr-192, Tyr-394 and Tyr-505. Hyperphosphorylated p56lck displayed retarded mobility on SDS gels, unaltered or marginally increased cytoskeletal association, and its catalytic activity changed in a biphasic manner; during the first 10-20 min of PAO-treatment the activity increased and then it declined to very low values within 1-2 hr. Our data suggest that p56lck contains both positive and negative regulatory sites which are constantly dephosphorylated at an unexpectedly high rate by cellular phosphotyrosine phosphatases.


Subject(s)
Arsenicals/pharmacology , Protein Tyrosine Phosphatases/antagonists & inhibitors , Protein-Tyrosine Kinases/metabolism , Animals , Cell Line, Transformed , Cytoskeleton/metabolism , Enzyme Activation , Humans , Lymphocyte Specific Protein Tyrosine Kinase p56(lck) , Mice , Peptide Mapping , Phosphorus Radioisotopes , Phosphorylation , Protein Tyrosine Phosphatases/metabolism , Tumor Cells, Cultured
16.
Eur J Immunol ; 24(1): 234-8, 1994 Jan.
Article in English | MEDLINE | ID: mdl-8020561

ABSTRACT

Activation of resting T lymphocytes by ligands to the T cell receptor (TcR)/CD3 complex is initiated by phosphorylation of a number of key regulatory proteins on specific tyrosine residues. One such protein is the heterodimeric enzyme phosphatidylinositol-3-kinase (PI3K). We recently found that this enzyme is also rapidly activated following TcR/CD3 triggering and that immunoprecipitated PI3K was activated in vitro by direct tyrosine phosphorylation. Here we show that TcR/CD3-induced tyrosine phosphorylation and activation of PI3K in Jurkat T leukemia cells depend on the presence of the p56lck tyrosine kinase: in a variant of the Jurkat T cell line lacking p56lck, JCaM1, these responses were absent. We also show that p56lck directly activates PI3K purified from transfected COS-1 cells, indicating that other T cell-specific proteins are not required for the process. Finally, tryptic peptide maps show that p56lck phosphorylates three tyrosine residues in the p85 alpha subunit of PI3K and two in p110 of PI3K. Our results suggest that p56lck is required for activation of PI3K in Jurkat T cells and can itself directly activate it by phosphorylating one or several stimulatory sites.


Subject(s)
Phosphotransferases (Alcohol Group Acceptor)/metabolism , Protein-Tyrosine Kinases/physiology , T-Lymphocytes/enzymology , Enzyme Activation , Humans , Immunoblotting , Lymphocyte Specific Protein Tyrosine Kinase p56(lck) , Peptide Mapping , Phosphatidylinositol 3-Kinases , Phosphorylation , Precipitin Tests , Tumor Cells, Cultured
17.
Eur J Haematol ; 49(4): 208-14, 1992 Oct.
Article in English | MEDLINE | ID: mdl-1281455

ABSTRACT

Tyrosine phosphorylation and dephosphorylation are implicated in the regulation of cell growth and differentiation. A diverse identification of key regulatory proteins by their content of phosphotyrosine has been hampered by the very low level of tyrosine phosphorylation. This is presumably caused by the relative preponderance of phosphotyrosine phosphatase activity in many cells. We report that treatment of hematopoietic cells with phenylarsine oxide (PAO), a membrane-permeable phosphotyrosine phosphatase inhibitor, induced a dramatic accumulation of phosphotyrosine in a number of cellular proteins. No changes in serine or threonine phosphorylation were detected. The PAO-induced accumulation of phosphotyrosine occurred well before any signs of toxicity or irreversible damage to the cells were seen. Addition of dithiothreitol reversed the effect of PAO. Our data demonstrate that phosphotyrosine phosphatase activity has a major impact on the level of phosphotyrosine in cellular proteins, even in cells with high protein tyrosine kinase activity. Cells with constitutively elevated tyrosine kinase activity are easily detected following treatment with PAO and substrates with an otherwise too low phosphotyrosine content or too rapid phosphate turnover can be studied. This effect of PAO allows determinations of tyrosine phosphorylation-dependent complex formation between proteins.


Subject(s)
Arsenicals/pharmacology , Blood Platelets/drug effects , Granulocytes/drug effects , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/blood , Aged , Animals , Blood Platelets/metabolism , Busulfan/therapeutic use , Cell Line , Dithiothreitol/pharmacology , Gene Rearrangement , Granulocytes/metabolism , Humans , Hydroxyurea/therapeutic use , Karyotyping , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Male , Mice , Phosphates/blood , Phosphoproteins/blood , Phosphoproteins/isolation & purification , Phosphorylation , Phosphotyrosine , Protein Tyrosine Phosphatases/antagonists & inhibitors , Tyrosine/analogs & derivatives , Tyrosine/analysis
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