High impact information on fln

• Flightin is essential for thick filament assembly and sarcomere stability in Drosophila flight muscles [1].
• We have created a null mutation for flightin, fln(0), that results in loss of flight ability but has no effect on fecundity or viability [1].
• These features suggest a role for flightin in the regulation of contraction, possibly by modulating actin-myosin interaction [2].
• Zeelin 2, which is on the outside of Lethocerus flight muscle thick filaments, has been sequenced and because of the similarity to Drosophila flightin, is re-named flightin [3].
• We propose that flightin is a major contributor to myofilament stiffness and a key determinant of the enhanced delayed force response to stretch in Drosophila flight muscles [4].

Biological context of fln

• Flight muscle properties and aerodynamic performance of Drosophila expressing a flightin transgene [5].
• These results illustrate the importance of flightin in flight muscle development and function [5].
• These results suggest that regulation of flightin protein level is independent of gene copy number and that the number of thick filaments assembled per myofibril is influenced independently by myosin and flightin expression [5].
• Nine of the eleven isoelectric variants of flightin are generated in vivo by multiple phosphorylations [6].
• We describe the generation and characterization of Df(3L)fln1, a lethal genetic deficiency in the 76BE region of the third chromosome which deletes several genes, including the gene for flightin [7].

Anatomical context of fln

• In intact muscles flightin is associated with the A band of the sarcomere, where evidence suggests it interacts with the myosin filaments [2].
• Mutations that affect flightin expression in Drosophila alter the viscoelastic properties of flight muscle fibers [4].

Physical interactions of fln

• Here, two different solid-state binding assays demonstrate that flightin binds to myosin and to a recombinant fragment of the myosin rod that include the COOH-terminal 600 amino acids (zone 19 to tail piece) [8].

Enzymatic interactions of fln

• The mutations are associated with age-dependent, site-specific degradation of myosin heavy chain and failure to accumulate phosphorylated forms of flightin, an indirect flight muscle-specific protein previously localized to the thick filament [9].

Regulatory relationships of fln

• Mutations in the myosin heavy-chain gene that prevent thick filament assembly block accumulation of all flightin variants except N1, the unphosphorylated precursor, which is present at much reduced levels [6].

References