Cell Signaling Technology

Product Pathways - Cytoskeletal Signaling

Phospho-Myosin Light Chain 2 (Ser19) Mouse mAb #3675

Applications Reactivity Sensitivity MW (kDa) Isotype
W IF-IC H M R (Z) Endogenous 18 Mouse IgG1

Applications Key:  W=Western Blotting  IF-IC=Immunofluorescence (Immunocytochemistry)
Reactivity Key:  H=Human  M=Mouse  R=Rat  Z=Zebra Fish
Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

Phospho-Myosin Light Chain 2 (Ser19) Mouse mAb detects endogenous levels of myosin light chain 2 (smooth muscle) only when phosphorylated at serine 19. This antibody does not cross-react with the cardiac isoform of myosin light chain 2.

Source / Purification

Monoclonal antibody is produced by immunizing mice with a synthetic phospho-peptide (KLH-coupled) corresponding to residues surrounding Ser19 of human myosine light chain 2 (smooth muscle).

Western Blotting

Western Blotting

Western blot analysis of extracts from HEK293, C2C12, and C6 cells, untreated (-) or lamda phosphatase treated (+), using Myosin Light Chain 2 Antibody #3672 (upper) or Phospho-Myosin Light Chain 2 (Ser19) Mouse mAb (lower).

IF-IC

IF-IC

Confocal immunofluorescent images of HeLa cells, untreated (left) or phosphatase-treated (right), labeled with Phospho-Myosin Light Chain 2 (Ser19) Mouse mAb (green). Actin filaments have been labeled with Alexa Fluor® 555 phalloidin (red). Blue pseudocolor = DRAQ5™ (fluorescent DNA dye).

Background

Myosin is composed of six polypeptide chains: two identical heavy chains and two pairs of light chains. Myosin light chain 2 (MLC2), also known as myosin regulatory light chain (MRLC or RLC, LC20), has many isoforms depending on its distribution. In smooth muscle, MLC2 is phosphorylated at Thr18 and Ser19 by myosin light chain kinase (MLCK) in a Ca2+/calmodulin-dependent manner (1). This phosphorylation is correlated with myosin ATPase activity and smooth muscle contraction (2). ROCK also phosphorylates Ser19 of smooth muscle MLC2, which regulates the assembly of stress fibers (3). Phosphorylation of smooth muscle MLC2 at Ser1/Ser2 and Ser9 by PKC and cdc2 has been reported to inhibit myosin ATPase activity (4,5). Phosphorylation by cdc2 controls the timing of cytokinesis (5). Transgenic mice lacking phosphorylation sites on the cardiac muscle isoform show morphological and functional abnormalities (6).

  1. Ikebe, M. and Hartshorne, D.J. (1985) J. Biol. Chem. 260, 10027-10031.
  2. Tan, J. L. et al. (1992) Annu. Rev. Biochem. 61, 721-759.
  3. Totsukawa, G. et al. (2000) J. Cell Biol. 150, 797-806.
  4. Ikebe, M. et al. (2000) J. Biol. Chem. 262, 9569-9573.
  5. Satterwhite, L. L. et al. (1992) J. Cell Biol. 118, 595-605.
  6. Sanbe, A. et al. (1999) J. Biol. Chem. 274, 21085-21094.

Application References

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This product is for in vitro research use only and is not intended for use in humans or animals. This product is not intended for use as therapeutic or in diagnostic procedures.

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