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- Beckman-Sundh, Ulla, et al.
(author)
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A screening method for phosphohistidine phosphatase 1 activity
- 2011
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In: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 116:3, s. 161-168
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Journal article (peer-reviewed)abstract
- Introduction. Research in the field of protein-bound phosphohistidine phosphorylation has been hampered by the difficulties in analysis and detection of phosphohistidine. Therefore a screening method was developed primarily for the analysis of phosphohistidine phosphatase 1 (PHPT1) activity. Methods. A highly positively charged substrate, Ac-Val-Arg-Leu-Lys-His-Arg-Lys-Leu-Arg-pNA, containing the peptide surrounding the phosphorylated histidine in ion channel KCa3.1 was chemically phosphorylated using phosphoramidate. Excess phosphoramidate was removed by anion exchange chromatography using a micro spin column. After incubation of the eluate with PHPT1, the removed phosphate was bound on a consecutive anion exchange spin column. The eluate was assayed in a micro plate format for remaining phosphate in the substrate Ac-Val-Arg-Leu-Lys-His(P)-Arg-Lys-Leu-Arg-pNA. Histone H4, also highly positive in charge, was subjected to the same procedure to explore the possibility to use other substrates to PHPT1 in this assay format. Results. It was found that Ac-Val-Arg-Leu-Lys-His(P)-Arg-Lys-Leu-Arg-pNA and phosphohistone H4 were dephosphorylated by PHPT1. The apparent K(m) for Ac-Val-Arg-Leu-Lys-His(P)-Arg-Lys-Leu-Arg-pNA was in the order of 10 mu M. Using this method, phosphohistidine phosphatase activity was detected in mouse liver cell sap with Ac-Val-Arg-Leu-Lys-His(P)-Arg-Lys-Leu-Arg-pNA as substrate. Discussion. The described method for determination of PHPT1 activity is comparably much easier and faster than presently used methods for detection of phosphohistidine phosphatase activity. It is also sensitive, since the lower activity limit was 5 pmol phosphate released per min. It has the potential to be used both for more rapid screening for inhibitors and activators to phosphohistidine phosphatases and for screening of histidine kinases.
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| 2. |
- Ek, Pia, et al.
(author)
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Identification and characterization of a mammalian 14-kDa phosphohistidine phosphatase
- 2002
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In: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 269, s. 5016-5023
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Journal article (peer-reviewed)abstract
- Protein histidine phosphorylation in eukaryotes has beensparsely studied compared to protein serine/threonine andtyrosine phosphorylation. In an attempt to rectify this byprobing porcine liver cytosol with the phosphohistidinecontainingpeptide succinyl-Ala-His(P)-Pro-Phe-p-nitroanilide(phosphopeptide I), we observed a phosphataseactivity that was insensitive towards okadaic acid andEDTA. This suggested the existence of a phosphohistidinephosphatase different from protein phosphatase 1, 2Aand 2C. A 1000-fold purification to apparent homogeneitygave a 14-kDa phosphatase with a specific activity of 3lmolÆmin)1Æmg)1 at pH 7.5 with 7 lM phosphopeptide Ias substrate. Partial amino-acid sequence determination ofthe purified porcine enzyme by MS revealed similaritywith a human sequence representing a human chromosome9 gene of hitherto unknown function. Molecularcloning from a human embryonic kidney cell cDNAlibraryfollowed by expression and purification, yielded aprotein with a molecular mass of 13 700 Da, and anEDTA-insensitive phosphohistidine phosphatase activityof 9 lmolÆmin)1Æmg)1 towards phosphopeptide I. Nodetectable activity was obtained towards a set of phosphoserine-,phosphothreonine-, and phosphotyrosine peptides.Northern blot analysis indicated that the humanphosphohistidine phosphatase mRNA was present preferentiallyin heart and skeletal muscle. These resultsprovide a new tool for studying eukaryotic histidinephosphorylation/dephosphorylation.
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| 3. |
- Ek, Pia, et al.
(author)
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Phosphohistidine phosphatase 1 (PHPT1) also dephosphorylates phospholysine of chemically phosphorylated histone H1 and polylysine
- 2015
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In: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 120:1, s. 20-27
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Journal article (peer-reviewed)abstract
- Background. Phosphohistidine phosphatase 1 (PHPT1), also named protein histidine phosphatase (PHP), is a eukaryotic enzyme dephosphorylating proteins and peptides that are phosphorylated on a histidine residue. A preliminary finding that histone H1, which lacks histidine, was phosphorylated by phosphoramidate and dephosphorylated by PHPT1 prompted the present investigation. Methods. Histone H1 and polylysine were phosphorylated at a low concentration (3.9 mM) of phosphoramidate. Their dephosphorylation by recombinant human PHPT1 was investigated by using a DEAE-Sepharose spin column technique earlier developed by us for studies on basic phosphoproteins and phosphopeptides. Determination of protein-bound, acid-labile phosphate was performed by a malachite green method. Mass spectrometry (MS) was used to investigate the occurrence of N-epsilon-phospholysine residues in a phosphorylated histone H 1.2 preparation, and to measure the activity of PHPT1 against free N-omega-phosphoarginine. Results. Histone H1.2, which lacks histidine, was phosphorylated by phosphoramidate on several lysine residues, as shown by MS. PHPT1 was shown to dephosphorylate phosphohistone H1 at a rate similar to that previously described for the dephosphorylation of phosphohistidine-containing peptides. In addition, phosphopolylysine was an equally good substrate for PHPT1. However, no dephosphorylation of free phosphoarginine by PHPT1 could be detected. Conclusion. The finding that PHPT1 can dephosphorylate phospholysine in chemically phosphorylated histone H1 and polylysine demonstrates a broader specificity for this enzyme than known so far.
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| 6. |
- Adolfsson, Päivi, 1956-, et al.
(author)
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Dietitians’ challenges when consulting to adults with intellectual disabilities
- 2019
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In: Tizard Learning Disability Review. - 1359-5474 .- 2042-8782. ; 24:4, s. 153-162
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Journal article (peer-reviewed)abstract
- Purpose: The purpose of this paper is to investigate registered dietitians' (RDs) experiences in consulting to adults with intellectual disabilities (ID) in Sweden.Design/methodology/approach: A descriptive study using a study-specific web-based questionnaire was administered, comprising both multiple-choice questions with a space for comments and open-ended questions. The open-ended answers and comments from 53 respondents were analysed with systematic text condensation.Findings: Four categories were identified: RDs' experiences from the first meeting; explanations for late initial contact; the actions taken by RDs; and necessary measures for more sustainable nutrition care. Ten sub-categories described the challenges that RDs experience in more detail.Practical implications: It is necessary to provide adults with ID and their supporting staff with individually tailored nutritional information. Individuals with ID must be actively involved in lifestyle changes that affect their everyday life. The RD must be included in the interdisciplinary team supporting adults with ID. If a new practice is to be implemented, it should be compatible with the existing values of adults with ID and their staff and must be feasible to implement in the everyday life of the individual.Originality/value: This paper identified several barriers that should be overcome in relation to the preparation of RDs for consultation with adults with ID about nutritional health issues. A systematic structure, knowledge about nutrition and knowledge about adults with ID and their living situations are needed. An assessment instrument may meet health promotion needs and facilitate longitudinal follow-ups of nutritional problems.
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| 7. |
- Adolfsson, Päivi, et al.
(author)
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Dietitians’ endeavor to contribute to the nutritional health of children and youth with intellectual disability and autism
- 2023
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In: International Journal of Developmental Disabilities. - : Taylor & Francis. - 2047-3869.
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Journal article (peer-reviewed)abstract
- The aim of the present study was to explore the experiences of registered dietitians (RD) who consult children and youth with intellectual disability (ID) and autism. Another aim was to investigate how knowledge and working methods were transferred to RDs working with adults with ID and autism. Twenty-six RDs completed a web-based study-specific questionnaire with multiple-choice and open-ended questions. The respondents’ comments and responses to the open-ended questions were analyzed using systematic text condensation. The analyses resulted in four categories: Reachability and accessibility of RDs, Clients do not comply with RDs’ dietary advice, RD finds individual solutions and Better collaboration for better knowledge. It was noteworthy that RDs’ undergraduate education did not prepare them for clients with ID and autism. Instead, they learned by doing and from other professionals at the clinic if they collaborate with them or were part in teams around the client. The RDs reported a lack of national routines for the transition process of nutrition support from young to adult.
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| 8. |
- Adolfsson, Päivi, 1956-, et al.
(author)
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Significant others’ perspectives on experiences of meal-oriented support and diet counselling for adults with intellectual disabilities who live in supported housing
- 2022
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In: International Journal of Developmental Disabilities. - : Taylor & Francis. - 2047-3869 .- 2047-3877. ; , s. 1-9
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Journal article (peer-reviewed)abstract
- The quality of meal-oriented support for people with intellectual disabilities is important for their health. The aim of the present study was to explore the experiences of meal-oriented support and diet counselling for adults with intellectual disabilities living in supported housing, from the perspective of housing staff and mothers. Five focus group interviews, including nine supporting staff members and nine mothers, were conducted. The interviews were analyzed using systematic text condensation. Five themes appeared; Extensive needs of the individual, Staff skills determine the food intake, Informal caregivers make up for shortage of support, Effective collaboration with a registered dietitian is needed and Responsibility of the organization state that professionalization of staff is needed. Lacking resources, such as time and nutritional knowledge, insufficient considerations of individual needs, and high staff turnover influence the meal-orientated services negatively. This study brings to the fore, staff working practices and the complexity of providing meal-oriented support for people with intellectual disabilities. Staff need skills to perform individually tailored support. This is best accomplished through effective collaboration between housing staff and relatives underpinned by knowledge from a registered dietitian. The working practices must be structured at the organizational level of the services.
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| 9. |
- Alexandridis, Vasileios, et al.
(author)
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Retropubic slings are more efficient than transobturator at 10-year follow-up : a Swedish register-based study
- 2023
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In: International Urogynecology Journal. - : Springer Science and Business Media LLC. - 0937-3462 .- 1433-3023. ; 34:6, s. 1307-1315
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Journal article (peer-reviewed)abstract
- Introduction and hypothesis: Long-term performance of mid-urethral slings (MUS) and potential differences between the retropubic and the transobturator technique for insertion are scarcely studied. This study aims to evaluate the efficacy and safety 10 years after surgery and compare the two main surgical techniques used. Methods: Women who underwent surgery with a MUS between 2006 and 2010 were identified using the Swedish National Quality Register of Gynecological Surgery and were invited 10 years after the operation to answer questionnaires regarding urinary incontinence and its impact on quality-of-life parameters (UDI-6, IIQ-7) and impression of improvement, as well as questions regarding possible sling-related complications and reoperation. Results: The subjective cure rate reported by 2421 participating women was 63.3%. Improvement was reported by 79.2% of the participants. Women in the retropubic group reported higher cure rates, lower urgency urinary incontinence rates and lower UDI-6 scores. No difference was shown between the two methods regarding complications, reoperation due to complications or IIQ-7 scores. Persisting sling-related symptoms were reported by 17.7% of the participants, most commonly urinary retention. Mesh exposure was reported by 2.0%, reoperation because of the tape by 5.6% and repeated operation for incontinence by 6.9%, significantly more in the transobturator group (9.1% vs. 5.6%). Preoperative urinary retention was a strong predictor for impaired efficacy and safety at 10 years. Conclusions: Mid-urethral slings demonstrate good results for the treatment of stress urinary incontinence and tolerable complication profiles in a 10-year perspective. The retropubic approach displays higher efficacy than the transobturator, with no difference regarding safety.
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| 10. |
- Beckman Sundh, Ulla, 1953-
(author)
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Studies on Phosphohistidine Phosphatase 1 : What? Where? Why?
- 2012
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Doctoral thesis (other academic/artistic)abstract
- Phosphohistidine phosphatase 1 (PHPT1) is a small protein, consisting of 125 amino acids, that catalyzes the dephosphorylation of histidine but does not have any activity towards other phosphorylated amino acids. PHPT1 was identified in 2002, and is so far the only mammalian histidine phosphatase known, but still little is known about its physiological role. No mammalian histidine kinases have hitherto been identified.Phosphorylation is one of the most important ways in which the structure and activity of a protein may be changed after translation. Proteins are phosphorylated on the side chain of amino acid residues. When a hydroxyl is phosphorylated the result is a phosphoester and when a nitrogen is phosphorylated the result is a phosphoamidate. Histidine may be phosphorylated on either of the two nitrogens of the imidazole ring of the side chain. The resulting phosphoamidate bond is labile and rich in energy, which makes histidine phosphorylation highly reversible and flexible. However, histidine phosphorylation is less studied than that of the phosphoesters due to the acid lability of the phosphoamidate bond.The work described in this thesis was focused on further elucidating the physiological role of PHPT1. Amino acid residues of importance for the activity of PHPT1 were identified, and mutants with decreased phosphatase activity were produced. These mutants have been used in studies on the function of PHPT1. By using immunohistochemical methodology the localization of PHPT1 in both mouse and human tissues was determined, with mainly similar results. A general finding was that expression of PHPT1 was high in epithelial cells with short turnover time, indicating that PHPT1 may have an important role in proliferating cells. We have also developed a comparatively fast and simple screening method for determination of PHPT1 activity. Since research in this field has been hampered by the lack of efficient and practical methodology, hopefully this new method will be an asset in search of inhibitors for PHPT1, which in turn may be used for detection of the elusive mammalian histidine kinases, the finding of which may give major breakthroughs in the field.
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