| 1. |
- Larsson, Annika, et al.
(författare)
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Signs of cross-seeding : aortic medin amyloid as a trigger for protein AA deposition
- 2011
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Ingår i: Amyloid. - : Informa UK Limited. - 1350-6129 .- 1744-2818. ; 18:4, s. 229-234
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Tidskriftsartikel (refereegranskat)abstract
- The highly diverse deposition pattern displayed by systemic amyloidoses, sometimes within the same amyloid disease, remains unexplained. The localized medin (AMed) amyloidosis develops from the precursor protein lactadherin and deposits in the media of the thoracic aorta in almost all individuals above 50 years of age. Given its high prevalence in the population, and the fact that systemic amyloidoses also deposit in the aorta, led us to investigate whether AMed amyloid could influence the tissue distribution of serum amyloid A derived (AA) amyloidosis. Seven aortas from patients with diagnosed systemic AA amyloidosis were investigated. Four displayed partial co-localization between medin and AA aggregates when examined with double-labeling immunofluorescence. Furthermore, in vitro studies showed that AMed amyloid-like fibrils promote the aggregation of protein AA into fibrils. The findings indicate that the highly frequent "senile" amyloidoses may have the potential to initiate fibril formation of the more uncommon amyloidoses by a cross-seeding mechanism.
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| 2. |
- Malmström Rognes, Åsa
(författare)
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Family Matters : Essays on Families, Firms and Funding in the Philippines 1850–2014
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Family Matters – Essays of Families, Firms and Funding in the Philippines 1850–2014 is a study of family business groups in the Philippines. It consists of an introductory essay and four separate papers. The introductory essay frames the thesis in the vast literature on family firms and family business groups in emerging economies, discusses sources and methodology, and provides an overview of Philippine economic history to give the overarching economic context to the separate papers. The first paper deals with the role of institutions in understanding the dominance and prevalence of family business groups in the Philippines. The literature posits that weak institutions can help explain the predominance of family business groups in emerging economies. This paper takes a historical perspective to examine whether that explanation holds over time, examining the development of core property rights and core economic institutions over time and how family firms have responded. The second paper studies funding options in the late nineteenth and early twentieth centuries and whether the rapidly growing financial system was driven from above or below. The paper examines the impact it had on the explicit goal of stimulating investment and growth in the early twentieth century and what that meant for family firms. The third paper studies capital market developments since the Asian crisis and in particular the growth of the corporate bond market in the Philippines; how this development and how it affected family business groups. The fourth paper deals with governance and management capabilities and examines professionalization of family firms over time to seek to answer the question of longevity. Management literature provides studies and models for family firms but these are fairly recent whereas the family firms that have been in business for several generations have found ways to manage for the long term. The paper analyses what three select groups have done in terms of professionalization and management.
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| 3. |
- Malmström, Susanna, et al.
(författare)
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A calmodulin-stimulated Ca2+-ATPase from plant vacuolar membranes with a putative regulatory domain at its N-terminus
- 1997
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Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 400:3, s. 324-328
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Tidskriftsartikel (refereegranskat)abstract
- A cDNA, BCA1, encoding a calmodulin-stimulated Ca2+-ATPase in the vacuolar membrane of cauliflower (Brassica oleracea) was isolated based on the sequence of tryptic peptides derived from the purified protein. The BCA1 cDNA shares sequence identity with animal plasma membrane Ca2+-ATPases and Arabidopsis thaliana ACA1, that encodes a putative Ca2+ pump in the chloroplast envelope. In contrast to the plasma membrane Ca2+-ATPases of animal cells, which have a calmodulin-binding domain situated in the carboxy-terminal end of the molecule, the calmodulin-binding domain of BCA1 is situated at the amino terminus of the enzyme.
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| 4. |
- Malmström, Susanna, et al.
(författare)
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Regulatory role of the N terminus of the vacuolar calcium-ATPase in cauliflower
- 2000
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 122:2, s. 517-526
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Tidskriftsartikel (refereegranskat)abstract
- The vacuolar calmodulin (CaM)-stimulated Ca2+-ATPase, BCA1p, in cauliflower (Brassica oleracea) has an extended N terminus, which was suggested to contain a CaM-binding domain (S. Malmstrom, P. Askerlund, M.G. Palmgren [1997] FEBS Lett 400: 324328). The goal of the present study was to determine the role of the N terminus in regulating BCA1p. Western analysis using three different antisera showed that the N terminus of BCA1p is cleaved off by trypsin and that the N terminus contains the CaM-binding domain. Furthermore, the expressed N terminus binds CaM in a Ca2+dependent manner. A synthetic peptide corresponding to the CaM-binding domain of BCA1p (Ala-19 to Leu-43) strongly inhibited ATP-dependent Ca2+ pumping by BCA1p in cauliflower low-density membranes, indicating that the CaM-binding region of BCA1p also has an autoinhibitory function. The expressed N terminus of BCA1p and a synthetic peptide (Ala-19 to Met-39) were good substrates for phosphorylation by protein kinase C. Sequencing of the phosphorylated fusion protein and peptide suggested serine-16 and/or serine-28 as likely targets for phosphorylation. Phosphorylation of serine-28 had no effect on CaM binding to the alanine-19 to methionine-39 peptide. Our results demonstrate the regulatory importance of the N terminus of BCA1p as a target for CaM binding, trypsin cleavage, and phosphorylation, as well as its importance as an autoinhibitory domain.
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| 5. |
- Malmström, Susanna
(författare)
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Vacuolar Ca2+-ATPases in Plants. Regulation by calmodulin binding to a N-terminal autoinhibitory domain.
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The calcium ion (Ca2+) is essential for all plant and animal life. One important function of Ca2+ is as a second messenger in the responses of the cell to environmental and hormonal signals as well as in some intrinsic developmental processes. The intracellular concentration of Ca2+ must be strictly regulated, since a high concentration of free cytosolic Ca2+ is toxic. All eukaryotic cells carry calcium-transporting enzymes, Ca2+-ATPases, that pump Ca2+ out from the cytosol, across the plasma membrane or into the endo(sarco)plasmic reticulum and the vacuole. The Ca2+-ATPases have a high affinity for Ca2+ and keep the cytosolic free Ca2+ concentration at 100 — 200 nM. In mammalians, seven Ca2+-ATPase genes have been identified, while in the model plant Arabidopsis thaliana eleven Ca2+-ATPases have been identified. Ca2+-ATPases can be divided into two major groups: those that bind and are stimulated by calmodulin (CaM) and those that are not. The cDNA, BCA1 (Brassica oleracea Ca2+-ATPase 1), for a vacuolar, CaM-stimulated Ca2+ -ATPase from cauliflower was cloned by PCR, based on sequence information from tryptic peptides obtained from the CaM-affinity-purified protein. The location to the vacuolar membrane was confirmed by confocal immunomicroscopy on sections from cauliflower inflorescence. The CaM-binding domain was identified within the first 43 amino acids in the N terminus, which is in contrast to the animal plasma membrane Ca2+-ATPases which have their CaM-binding domain in the C terminus. The N terminus of BCA1 was expressed as a fusion protein and shown to bind CaM in a Ca2+-dependent fashion. Results from inhibition studies with a peptide corresponding to the CaM-binding domain of BCA1, indicate that the N terminus also functions as an autoinhibitor. The autoinhibitory domain overlaps at least partially with the CaM-binding domain. In vitro phosphorylation studies and controlled proteolysis suggest that the BCA1 N terminus probably also is a target for phosphorylation and regulatory proteolysis. Taken together, the results demonstrate the regulatory importance of the N terminus of BCA1 as a target for CaM binding, trypsin cleavage, and possibly phosphorylation, as well as its importance as an autoinhibitory domain. BCA1 was the first plant Ca2+-ATPase cloned for which a Ca2+-pumping activity had been shown for the corresponding gene product, and also the first Ca2+-ATPase shown to have a CaM-binding domain at its N terminus. The N-terminal location of the CaM-binding regulatory domain has later turned out to be a typical feature of CaM-stimulated Ca2+-ATPases in plants. The cloning and characterization of a vacuolar CaM-stimulated Ca2+-ATPase from Arabidopsis, ACA4 (Arabidopsis Ca2+-ATPase 4) is also described. ACA4 is 84% identical to BCA1, contains an N-terminal CaM-binding domain, and was shown to localize to small vacuoles in Arabidopsis protoplasts. Overexpression of activated ACA4 protected Arabidopsis seedlings against elevated NaCl in the growth medium, indicating a role for ACA4 in response to salt stress and one possible physiological function of a Ca2+-ATPase in planta.
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