High impact information on Strn-Mlck

• We report here that myosin light chain kinase-dependent phosphorylation is not required for myofibrillogenesis or for the development of maximal isometric force in indirect flight muscles [1].
• Myosin regulatory light chain is phosphorylated by myosin light chain kinase at conserved serine and threonine residues in a number of species [1].
• The activity of smooth muscle/non-muscle myosin II is regulated by phosphorylation of the regulatory light chains, that in turn is modulated by the antagonistic activity of myosin light chain kinase and myosin light chain phosphatase [2].
• Similarly, the 5' end of the Stretchin-Mlck transcription unit can also express transcripts encoding kettin and Unc-89-like isoforms, which share no sequences with the MLCK-like transcripts [3].
• In addition, the 3' end of the stretchin-MLCK transcription unit expresses shorter transcripts that encode 86 to 165 kDa isoforms of stretchin-MLCK that are analogous to vertebrate Myosin light chain kinases [3].

Biological context of Strn-Mlck

• CONCLUSION: In Drosophila, a single MLCK gene produces multiple isoforms whose regulatory regions and expression patterns are different [4].
• Genomic Southern analysis and chromosome hybridization suggest mlck is a single copy gene which maps to chromosome band 52D, and is not haplo-insufficient for flight [5].
• Protein motifs I and II, which are present in vertebrate nonmuscle and smooth muscle myosin light chain kinase, but not in skeletal muscle myosin light chain kinase, are also present in Drosophila myosin light chain kinase [5].
• However, activation studies for skeletal muscle myosin light chain kinase (SK-MLCK) established that all of the multiple binding site mutants are poor activators of SK-MLCK [6].

Anatomical context of Strn-Mlck

• We assessed the in vivo role of myosin regulatory light chain phosphorylation in the striated muscles of Drosophila melanogaster by substituting alanine at each or both conserved myosin light chain kinase-dependent phosphorylation sites, serine 66 and serine 67 [1].
• Myosin light chain kinases (MLCK) are a family of signaling proteins that are required for cytoskeletal remodeling in myocytes [7].
• When larva or late pupa myosin was incubated with myosin light chain kinase from chicken gizzard or adult flies, phosphorylation of Lt1, Lf2' and Lt2' occurred [8].

Physical interactions of Strn-Mlck

• Solution structure of calmodulin and its complex with a myosin light chain kinase fragment [9].

Analytical, diagnostic and therapeutic context of Strn-Mlck

• This integrated study uses site-directed mutagenesis to examine the relationship between removal of the myosin light chain kinase (MLCK) phosphorylation site, in vivo function of the flight system (flight tests, wing kinematics, metabolism, power output), isolated IFM fiber mechanics, MLC2 isoform pattern, and sarcomeric ultrastructure [10].

References