A myosin phosphatase targeting subunit isoform transition defines a smooth muscle developmental phenotypic switch

• DOI: 10.1152/ajpcell.2000.278.3.c589
• Publication Date: 2017-12-24T22:27:20Z
• Authors: Wessel P. Dirksen; Franjo Vladic; Steven A. Fisher
• Keywords: Myosin-light-chain phosphatase

Smooth muscle myosin phosphatase dephosphorylates the regulatory light chain and thus mediates smooth relaxation. The activity of this is dependent upon its myosin-targeting subunit (MYPT1). Isoforms MYPT1 have been identified, but how they are generated their relationship to phenotypes not clear. Cloning middle section chicken rat genes revealed that each gene gave rise isoforms by cassette-type alternative splicing exons. In chicken, a 123-nucleotide exon was included or excluded from mature mRNA, whereas in two exons immediately downstream were alternative. lacking only detected tissues display phasic contractile properties, isoform ratios variable. patterns expression mRNA more complex, with three major minor present all at varying stoichiometries. Isoform switching identified developing gizzard, which exon-skipped replaced exon-included around time hatching. This switch occurred after transitions heavy (MLC 17 ) correlated severalfold increase rate developmental good model for determining mechanisms significance muscle.