Linked Life Data

7542009

Source:http://linkedlifedata.com/resource/pubmed/id/7542009

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1995-8-18
pubmed:abstractText
B lymphocytes must respond to low concentrations of antigen despite having low affinity antigen receptors during the primary immune response. CD19, a B cell-restricted membrane protein of the immunoglobulin superfamily that associates with the antigen receptor complex, may help the B cell meet this requirement. Cross-linking CD19 to membrane immunoglobulin (mIg) lowers, by two orders of magnitude, the number of mIg that must be ligated to activate phospholipase C (PLC) or to induce DNA synthesis. CD19 is coupled, via protein tyrosine kinases (PTKs), to PLC and phosphatidylinositol 3' kinase (PI3' kinase), and it interacts with the Src-type nonreceptor PTK lyn. It also associates with two other membrane proteins, CR2 (complement receptor type 2, CD21), which permits nonimmunologic ligation of CD19, and TAPA-1, a member of the tetraspan family of membrane proteins. CR2 binds fragments of C3 that are covalently attached to glycoconjugates. This indirectly enables CD19 to be cross-linked to mIg after preimmune recognition of an immunogen by the complement system. CR2 also can be ligated by CD23, a lectin-like membrane protein that resides on cells that may present antigen to B cells. TAPA-1 associates with several other membrane proteins on B and T cells, including MHC class II, CD4, and CD8, and it promotes Ca2(+)- and LFA-1-independent homotypic aggregation when ligated directly or indirectly through CD19 or CR2. This may facilitate interaction of the B cell with other cells essential for cellular activation. The formation of this membrane protein complex by representatives of three different protein families helps the B cell resolve its dilemma of combining broad specificity with high sensitivity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0732-0582
pubmed:author
pubmed:issnType
Print
pubmed:volume
13
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
127-49
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
The CD19/CR2/TAPA-1 complex of B lymphocytes: linking natural to acquired immunity.
pubmed:affiliation
Wellcome Trust Immunology Unit, University of Cambridge School of Clinical Medicine, United Kingdom.
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't