Phospho-Myosin Light Chain 2 (

3674:

Immunofluorescence , Western Blotting

Phospho-Myosin Light Chain 2 (Thr18/Ser19) Antibody detects endogenous levels of myosin light chain 2 (smooth muscle) only when dually phosphorylated at threonine 18 and serine 19. The antibody does not cross-react with the cardiac isoform of myosin light chain 2.

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Thr18/Ser19 of human myosin light chain 2. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western blot analysis of extracts from HEK293 cells stimulated with ionophore A23187 for the indicated times, using Phospho-Myosin Light Chain 2 (Thr18/Ser19) Antibody.

IF-IC

Confocal immunofluorescent analysis of HeLa cells, untreated (left) or λ phosphatase-treated (right), using Phospho-Myosin Light Chain 2 (Thr18/Ser19) Antibody (green). Actin filaments have been labeled with Alexa Fluor 555 phalloidin (red). Blue pseudocolor = DRAQ5® (fluorescent DNA dye).

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.

• Birukova, A. A. et al. (2004) Microtubule Disassembly Induces Cytoskeletal Remodeling and Lung Vascular Barrier Dysfunction: Role of Rho-Dependent Mechanisms. J. Cellular Phys. 201, 55-50. Applications: IC-IF Western Blotting
• Watanabe, T. et al. (2007) Mol Biol Cell 18, 605-16. Applications: Western Blotting
• Bhadriraju, K. et al. (2007) BMC Cell Biol 8, 43. Applications: IF-IC (In Cells) Western Blotting
• Ponsaerts, R. et al. (2008) Invest Ophthalmol Vis Sci 49, 4816-27. Applications: IF-IC (In Cells)
• Li, Z. et al. (2006) Mol Cell Biol 26, 4240-56. Applications: Western Blotting

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• 3671 Phospho-Myosin Light Chain 2 (Ser19) Antibody
• 7074 Anti-rabbit IgG, HRP-linked Antibody
• 7720 Prestained Protein Marker, Broad Range (Premixed Format)
• 7727 Biotinylated Protein Ladder Detection Pack
• 7003 20X LumiGLO^® Reagent and 20X Peroxide
• 3672 Myosin Light Chain 2 Antibody
• 3675 Phospho-Myosin Light Chain 2 (Ser19) Mouse mAb

For Research Use Only. Not For Use In Diagnostic Procedures.