BD Transduction Laboratories™ Purified Mouse Anti-MYPT1

Protein phosphatase-1 (PP1) is a major serine/threonine phosphatase that is involved in various cellular processes in eukaryotic cells. The PP1 catalytic subunit may be directed to particular subcellular locations by targeting subunits, which can modify the substrate specificity of the enzyme. The PP1 enzyme associated with the myofibrils of striated and smooth muscle forms a complex with Myosin Phosphatase Targeting subunit 1 (MYPT1). MYPT1 contains seven ankyrin repeats in the N-terminal region, and a leucine zipper (LZ) motif in the C-terminus. Alternative splicing of the MYPT1 mRNA leads to expression of a truncated MYPT1 that lacks the leucine zipper region. The expression of MYPT1 splice variants correlate with a smooth muscle phenotype. In the tonic contracting chicken aorta, only the full length MYPT1 is expressed, while in the phasic contracting chicken gizzard, only the truncated MYPT1 is expressed. The leucine zipper motif may be required for association with cGMP-dependent protein  kinase I. Thus, MYPT1 may direct not only PP1 enzymatic activity toward  myosin, but also may regulate the cGMP responsiveness of PP1 through expression of alternative splice variants.