What is IFM?


Indirect flight muscles (IFM): power-producing

muscles that move the wings indirectly by deformation of the thoracic exoskeleton (Crossley,1978). The IFM consist of two perpendiculary oriented, antagonistic muscles: the dorsolongitudinal muscles (DLM) and dorsoventral muscles (DVM) (Figure 1a). The DLM extend nearly parallel to the long body axis while the DVM extend from the tergum to the sternum. DLM function as wing depressors (downstroke) and their contraction stretches the DVM, which in turn contract to elevate the wings (upstroke) and stretch the DLM.


What is Flightin?

 The indirect flight muscles of Drosophila are adapted for rapid oscillatory movements which depend on properties of the contractile apparatus itself. Flight muscles are stretch activated and the frequency

of contraction in these muscles is independent of the

rate of nerve impulses. Little is known about the molecular basis of these adaptations. We now report

a novel protein that is found only in flight muscles

and has, therefore, been named flightin. Although we

detect only one gene (in polytene region 76D) for

flightin, this protein has several isoforms (relative gel

mobilities, 27-30 kD; pls, 4.6-6.0). These isoforms

appear to be created by posttranslational modifications.

A subset of these isoforms is absent in newly emerged

adults but appears when the adult develops the ability

to fly. In intact muscles flightin is associated with the

A band of the sarcomere, where evidence suggests it

interacts with the myosin filaments. Computer database searches do not reveal extensive similarity to any known protein. However, the NH2-terminal 12 residues show similarity to the NH2-terminal sequence of actin, a region that interacts with myosin. These features suggest a role for flightin in the regulation of contraction, possibly by modulating actin-myosin interaction.



Vigoreaux J. O., 2001. Genetics of the Drosophila flight muscle myofibril: a window into the biology of complex systems. BioEssays 23:1047-1063,

Flightin, a Novel Myofibrillar Protein of

Drosophila Stretch-activated Muscles

The Journal of Cell Biology, Volume 121, Number 3, May 1993 587-598

Research Interests

Our lab is interested in the structural and functional properties of muscles that power oscillatory systems, namely the insect flight muscle and the vertebrate cardiac muscle. We use classical and molecular genetic approaches to study the function of various contractile proteins of the indirect flight muscles (IFM) of Drosophila melanogaster. Our goal is to understand how individual proteins contribute to the structural stability and mechanical properties of the muscle fiber, and to the function of the flight system. This research combines biochemical techniques to analyze protein function, cell imaging techniques to analyze muscle ultrastructure, bioengineering techniques to analyze muscle mechanical properties, and entire flight system measurements. The second area of interest is thin filament regulation of cardiac muscle contraction. A major goal of this research is to understand how changes in phosphorylation of troponin I affect the contractile properties of the heart.

Vigoreaux Lab

The University of Vermont

March Life Science Bldg, Room 322

(802)-656-4627 (Office)

(802)-656-8654 (Lab)

(802)-656-2914 (Fax)


Email: Jim.Vigoreaux@uvm.edu