Anti-Phospho-MBS (MYPT1) (Thr853) pAb

WB - 0.4-1 ug/mL ELISA - 0.5-1 ug/mL

The expression of a constitutively active form of Rho-kinase can induce stress fiber and focal adhesion formation in fibroblasts and an increase in the level of myosin light chain (MLC20) phosphorylation in smooth muscle and in non-muscle cells (1). These results are attributed to an increase in MLC20 phosphorylation and this is thought to reflect the inhibition of myosin phosphatase (MP). MP is composed of three subunits: a catalytic subunit of type 1 phosphatase delta isoform, PP1c delta, and two non-catalytic subunits, 110 and 20 kDa. The 110 kDa subunit is a targeting molecule and has been termed myosin phosphatase target subunit 1 (MYPT1) or myosin-binding subunit (MBS). MBS/MYPT1 is the key molecule involved in regulation of MP activity (2). Phosphorylation by Rho-kinase inhibits MP activity and this reflects a decrease in Vmax. Activity of MP with different substrates also is inhibited by phosphorylation. Two major sites of phosphorylation on chicken MBS/MYPT1 are Thr696 and Thr853. Various point mutations were designed for these phosphorylation sites. Following thiophosphorylation by Rho-kinase and assays of phosphatase activity it was determined that Thr695 was responsible for inhibition. Rho-kinase, which is activated by GTP-RhoA, phosphorylates MBS/MYPT1 and consequently inactivates myosin phosphatase (MP). Over-expression of RhoA or activated RhoA in NIH 3T3 cells increases phosphorylation of MBS/MYPT1 and MLC20. Thus, Rho appears to inhibit myosin phosphatase through the action of Rho-kinase.

1.0 mg/mL

Supplied in 20mM phosphatase buffer (pH 7.5), 300mM NaCl, 50% glycerol.

Human: 4759 Mouse: 23956

Thr853 phosphorylation of synthetic peptide near MBS/MYPT1 (binding KLH)

115 kDa

This polyclonal antibody is produced by immunizing rabbit with a synthetic phosphopeptide (KLH coupled) corresponding to residues surrounding Thr853 of human MBS/MYPT1. IgG is purified by peptide-Sepharose affinity chromatography.

MBS