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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1990-10-3
pubmed:abstractText
Calpain (EC 3.4.22.17; Ca2(+)-dependent cysteine endopeptidase) is known to exist in two forms of isozyme. Calpain I requires low (or microM)-Ca2+ for activation and calpain II requires high (or mM)-Ca2+. Both isozymes consist of one heavy (approx.80 kDa) and one light (approx. 30 kDa) subunit each. The heavy subunits of isozymes I and II are different genetic products, while the light subunits are identical. Antibodies respectively specific for the heavy subunits of pig calpains I and II were raised in rabbits, and the affinity-purified IgG proteins were used for Western blot analysis. When 23 human hematopoietic system cells were examined for the degree of their expression of the genes for calpains I and II, all of them were found to contain calpain I of detectable amounts in their cytosolic fluid. By contrast, only nine cell-line cells were positive in calpain II, and they were, without exception, the lineage which had been infected with HTLV-I, the retrovirus responsible for human adult T-cell leukemia. The enhanced production of calpain II in HTLV-I infected T-cells was also confirmed by running chromatographic analyses on the homogenates of these cells, and comparing them with those of uninfected T-cells. When YT-C3 cell, which is an uninfected, natural killer-like cell, was transfected with HTLV-I gene, the resulting transformed stable cells, YT-4 and YT-5.1, were found to produce increased amounts of calpain II concomitant with that of interleukin (IL)-2 receptor protein. These results suggest that the gene expression for calpain isozymes may vary during the course of differentiation of T-lymphocytes. The mechanism of regulation of calpain isozyme genes and the biological significance of the variation in expression during differentiation still remain unanswered.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0361-7742
pubmed:author
pubmed:issnType
Print
pubmed:volume
344
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
477-94
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Gene expression for calpain isozymes in human hematopoietic system cells.
pubmed:affiliation
Department of Clinical Science, Faculty of Medicine, Kyoto University, Japan.
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't