Linked Life Data

9242363

Source:http://linkedlifedata.com/resource/pubmed/id/9242363

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1997-8-21
pubmed:abstractText
Platelets, when released as anuclear cells by their precursor megakaryocytes, already carry soluble proteolytic fragments of the amyloid precursor protein (APP) within their alpha-granules and intact APP in the alpha-granule membranes. In response to activation signals elicited by physiologic stimuli such as thrombin, platelets release their granules' soluble contents and translocate granule membrane-bound proteins to the plasma membrane. Because platelets carry >90% of the circulation's APP, activated platelets have been implicated as origins of the beta-amyloid peptide fragment of APP (A beta), whose deposition in the cerebrovasculature is characteristic of Alzheimer's disease. We have therefore studied the APP contents and proteolytic processing in resting DAMI human megakaryocytic cells, along with the consequences of the activation of these cells by thrombin, comparing the results in each case to those with human platelets. Resting and PMA-differentiated DAMI cell contents were examined by Western blotting, immunoprecipitation, or metabolic labeling with sulfur 35-labeled methionine during culture, while plasma membrane-bound APP was evaluated by flow cytometry. Activation was followed by changes in cytoplasmic calcium concentration ((Ca++)in) and in membrane potential. Like platelets, DAMI cells exhibited a thrombin dose-dependent delta(Ca++)in, and membrane potential change; in contrast to the surface of a platelet, the surface of an agranular resting DAMI cell expresses granule-membrane proteins (APP and CD63) that appear on platelets only after activation. DAMI cell culture with 35S-labeled methionine confirmed that megakaryocytes synthesize large amounts of APP, of slightly higher molecular weight, and degrade their APP extensively before platelets are formed.
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-2143
pubmed:author
pubmed:issnType
Print
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21-32
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Stimulus responses and amyloid precursor protein processing in DAMI megakaryocytes.
pubmed:affiliation
Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.