An Alternatively Spliced Isoform of Non-muscle Myosin II-C Is Not Regulated by Myosin Light Chain Phosphorylation

We report a novel isoform of non-muscle myosin II-C (NM II-C), NM II-C2, that is generated by alternative splicing of an exon, C2, encoding 41 amino acids in mice (33 in humans). The 41 amino acids are inserted into loop 2 of the NM II-C heavy chain within the actin binding region. Unlike most verte...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2009-04, Vol.284 (17), p.11563-11571
Main Authors: Jana, Siddhartha S., Kim, Kye-Young, Mao, Jian, Kawamoto, Sachiyo, Sellers, James R., Adelstein, Robert S.
Format: Article
Language:English
Subjects:
Actins - chemistry
Alternative Splicing
Amino Acid Sequence
Animals
Chlorocebus aethiops
COS Cells
Dose-Response Relationship, Drug
Enzyme Catalysis and Regulation
Green Fluorescent Proteins - metabolism
Humans
Mice
Molecular Sequence Data
Myosin Light Chains - chemistry
Myosin Type II - chemistry
Neurons - metabolism
Phosphorylation
Sequence Homology, Amino Acid
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We report a novel isoform of non-muscle myosin II-C (NM II-C), NM II-C2, that is generated by alternative splicing of an exon, C2, encoding 41 amino acids in mice (33 in humans). The 41 amino acids are inserted into loop 2 of the NM II-C heavy chain within the actin binding region. Unlike most vertebrate non-muscle and smooth muscle myosin IIs, baculovirus-expressed mouse heavy meromyosin (HMM) II-C2 demonstrates no requirement for regulatory myosin light chain (MLC20) phosphorylation for maximum actin-activated MgATPase activity or maximum in vitro motility as measured by the sliding actin filament assay. In contrast, noninserted HMM II-C0 and another alternatively spliced isoform HMM II-C1, which contains 8 amino acids inserted into loop 1, are dependent on MLC20 phosphorylation for both actin-activated MgATPase activity and in vitro motility (Kim, K. Y., Kovacs, M., Kawamoto, S., Sellers, J. R., and Adelstein, R. S. (2005) J. Biol. Chem. 280 22769-22775). HMM II-C1C2, which contains both the C1 and C2 inserts, does not require MLC20 phosphorylation for full activity similar to HMM II-C2. These constitutively active C2-inserted isoforms of NM II-C are expressed only in neuronal tissue. This is in contrast to NM II-C1 and NM II-C0, both of which are ubiquitously expressed. Full-length NM II-C2-GFP expressed in COS-7 cells localizes to filaments in interphase cells and to the cytokinetic ring in dividing cells.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M806574200