Catalog # MP4201

Myosin Light Chain (a.a. 11-22) Antibody

Rabbit Polyclonal

Application / Dilution

Size 100 μl

Species Reactivity Hu, Rt, Ms, Ck

MW 20 kDa



Both smooth muscle and nonmuscle myosin II activity is regulated by the phosphorylation state of the myosin regulatory light chain (MLC, MRLC, MLC20, Myl9). Phosphorylation of MLC at Thr-18 and Ser-19 activates myosin II motor activity and increases myosin filament stability. This activation has important roles in various cell motile processes. By contrast, other phosphorylation sites on MLC may inhibit myosin II activity. PKC phosphorylates Ser-1/Ser-2 and Thr-9 in MLC, and this phosphorylation decreases activated myosin II interaction with actin, as well as inhibits MLC interaction with the activation site kinase, myosin light-chain kinase. The Ser-1/Ser-2 region may be the major inhibitory site since Ser-1 is phosphorylated during PDGF-induced stress fiber disassembly and expression of unphosphorylatable MLC20 at the Ser-1/Ser-2 site suppresses this disassembly. Thus, inhibition of myosin II activity through phosphorylation of Ser-1/Ser-2 may have important roles in growth factor-induced reorganization of actomyosin filaments.


Komatsu, S. & Ikebe, M. (2007) Mol. Biol. Cell 18:5081.
Tan, J.L. et al. (1992) Annu. Rev. Biochem. 61:721.
Sellers, J.R. (1991) Curr. Opin. Cell Biol. 3:98.

Western blot analysis of C2C12 cells untreated (lanes 1, 3, 5, & 7) or treated with Lambda phosphatase (lanes 2, 4, 6, & 8). The blots were probed with monoclonal anti-MLC20 (clone MY-21) (lanes 1 & 2), polyclonal anti-MLC (Ser-19) phosho-specific (lanes 3 & 4), anti-MLC (Ser-1) phosho-specific (lanes 5 & 6), or anti-MLC (a.a. 11-22) (lanes 7 & 8) .

Immunocytochemical labeling of phosphorylated MLC in paraformaldehyde fixed A7r5 cells. The cells were dual-labeled with anti-MLC (MM3441; middle) and anti-MLC (MP4201; top left), anti-MLC (Ser-19) (MP4221; middle left) and anti-MLC (Ser-1) (MP3461; bottom left). Goat anti-Mouse DyLight® 488 and Goat anti-Rabbit DyLight® 594 were used for detection of primary antibodies. The overlay of staining patterns are shown to the right.

MLC (a.a. 11-22) synthetic peptide (coupled to KLH) corresponds to amino acid residues in the N-terminus of human myosin regulatory light chain 12A (Myl12A). This peptide sequence is highly conserved in human, rat, mouse, chicken, and zebrafish Myl12A, and in other smooth muscle and non-muscle MLCs.

*For more information, see UniProt Accession P19105
Rabbit polyclonal, affinity-purified antibody is supplied in 100μl phosphate-buffered saline, 50% glycerol, 1 mg/ml BSA, and 0.05% sodium azide. Store at –20°C. Stable for 1 year.

The products are are safely shipped at ambient temperature for both domestic and international shipments. Each product is guaranteed to match the specifications as indicated on the corresponding technical data sheet. Please store at -20C upon arrival for long term storage.

This antibody was affinity purified using MLC (a.a. 11-22) peptide (without carrier). The antibody detects a 20 kDa* band corresponding to the molecular weight of myosin light chain in mouse C2C12, rat PC12, and human A431.

*All molecular weights (MW) are confirmed by comparison to Bio-Rad Rainbow Markers and to western blot mobilities of known proteins with similar MW.

This kit contains: