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Defective expressio...
Defective expression of beta 1-integrins in cells with constitutively active alpha L beta 2-integrins
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- Hedman, H. (author)
- Umeå universitet,Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet),University of Umeå
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- Alenius, Mattias (author)
- Umeå universitet,Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet),University of Umeå
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- Lundgren, E. (author)
- Umeå universitet,Institutionen för molekylärbiologi (Teknisk-naturvetenskaplig fakultet),University of Umeå
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(creator_code:org_t)
- Elsevier Science B.V., Amsterdam, 1997
- 1997
- English.
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In: Experimental Cell Research. - : Elsevier Science B.V., Amsterdam. - 0014-4827 .- 1090-2422. ; 232:2, s. 270-276
- Related links:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
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- We have investigated a potential relationship between expression of beta 1-integrins and adhesiveness of the beta 2-integrin LFA-1 (alpha L beta 2, CD11a/CD18). By an approach of random mutagenesis and selection we established clones from the human acute lymphatic leukemia cell line HPB-ALL with (i) constitutively active LFA-1 and (ii) with no apparent integrin-beta 1 cell surface expression. Thirty seven of 42 clones selected for activated LFA-1 were found to have lost apparent integrin-beta 1 expression. Conversely, 7 of 21 clones selected for lack of beta 1 expression were found to have activated LFA-1. Since this pointed toward a possible coupling between beta 1 expression and LFA-1 activity, we further analyzed at which level beta 1 expression was blocked. We focused on one clone, HAP4, with activated LFA-I and no detectable beta 1 cell surface expression and found, surprisingly, that it expressed wild-type levels of beta 1 mRNA and, in Western blots of whole cell lysates, apparently normal levels of beta 1 protein. However, in addition to beta 1 of the expected molecular weight, HAP4 expressed a unique 48-kDa band recognized by the polyclonal anti-beta 1 antiserum. Immunoprecipitation experiments revealed that the epitope recognized by the anti-beta 1 antibody 4B4 was hidden or lost. The alpha 4-chain was found in its precursor form but it did not associate with any beta-chain, and it was not processed to its mature form. Instead alpha 4-chains were eventually degraded. Taken together this showed that beta 1-chains were produced but not properly processed in HAP4. From this we propose that HAP4 is deficient in a gene product required both for proper beta 1 folding and for repression of LFA-1 adhesiveness.
Subject headings
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Immunologi inom det medicinska området (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Immunology in the medical area (hsv//eng)
Keyword
- MEDICINE
- MEDICIN
Publication and Content Type
- ref (subject category)
- art (subject category)
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