Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myosin light chain genes of human hematopoietic cells have not been fully characterized. We previously reported the cloning of the full-length cDNAs of 20 kDa regulatory myosin light chain (MLC-2), named as MLC-2A, from Meg-01, a human megakaryoblastic leukemia cell line (J. Smooth Muscle Res. 37: 25-38, 2001). We now cloned another MLC-2 isoforms from human platelets and U937, a human monocytic leukemia cell line, named as MLC-2B and MLC-2C, respectively. Both MLC-2A and MLC-2B consisted of three exons, which were situated on gene loci 18p1.3. Analysis of the gene structure indicated that MLC-2A and MLC-2B utilized different exons. MLC-2C also consisted of three exons, which was situated on gene loci 20p12. Amino acid sequence of MLC-2C was, of interest, apparently almost the same as that of MLC-2 from chicken gizzard smooth muscle LC20-A (one amino acid's difference) and human vascular smooth muscle LC-20 (two amino acids' difference). All three protein kinase C phosphorylation residues (Ser-1, Ser-2, Thr-9) and both myosin light chain kinase phosporylation residues (Thr-18, Ser-19) are conserved in these three isoforms. The MLC-2A and MLC-2B mRNA were expressed constitutively in all of the human hematopoietic cell lines examined and their expression levels were almost the same. On the other hand, MLC-2C mRNA was expressed in untreated monocytic cell lines (U937 and A-THP-1) and HL-60 differentiated into monocyte/macrophage cell lineage by TPA treatment. These results indicate that smooth muscle type isoform, MLC-2C is the inducible isoform, and might play a crucial role in monocyte/macrophage cell lineage.
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PMID:Smooth muscle type isoform of 20 kDa myosin light chain is expressed in monocyte/macrophage cell lineage. 1848 May 96