Catalog # MP4221

Myosin Light Chain (Ser-19), phospho-specific Antibody

Rabbit Polyclonal

Application / Dilution

ELISA	1:2000
ICC	1:100
WB	1:1000

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.

References

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.

Phospho-MLC (Ser-19) synthetic peptide (coupled to KLH) corresponds to amino acid residues surrounding Ser-19 in 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 cross-adsorbed to MLC (a.a. 11-22) then affinity purified using phospho-MLC (Ser-19) peptide (without carrier). The antibody detects a 20 kDa* band corresponding to the molecular weight of myosin light chain in human A431 treated with EGF and in mouse C2C12 treated with Calyculin A. This reactivity is not observed after lambda phosphatase treatment of MLC.

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

Product References:

Cao, Y. et al. (2018) Exp Cell Res. 373(1-2):119. (WB: human HeLa)
Ho, H. et al. (2013) Pigment Cell Melanoma Res. 26(2):218. (WB: human A375 melanoma)

This kit contains: