Drosophila Models Rediscovered with Super-Resolution Microscopy

Abstract

With the advent of super-resolution microscopy, we gained a powerful toolbox to bridge the gap between the cellular- and molecular-level analysis of living organisms. Although nanoscopy is broadly applicable, classical model organisms, such as fruit flies, worms and mice, remained the leading subjects because combining the strength of sophisticated genetics, biochemistry and electrophysiology with the unparalleled resolution provided by super-resolution imaging appears as one of the most efficient approaches to understanding the basic cell biological questions and the molecular complexity of life. Here, we summarize the major nanoscopic techniques and illustrate how these approaches were used in Drosophila model systems to revisit a series of well-known cell biological phenomena. These investigations clearly demonstrate that instead of simply achieving an improvement in image quality, nanoscopy goes far beyond with its immense potential to discover novel structural and mechanistic aspects. With the examples of synaptic active zones, centrosomes and sarcomeres, we will explain the instrumental role of super-resolution imaging pioneered in Drosophila in understanding fundamental subcellular constituents.

Peripheral thickening of the sarcomeres and pointed end elongation of the thin filaments are both promoted by SALS and its formin interaction partners

“…Over the past decade, nanoscopy became a powerful tool to reveal the molecular organization of various types of subcellular structures, such as the nuclear pore complex, centrosomes and synaptic active zones [ 45 , 46 ]. Beyond these, we have successfully used a dSTORM-based pipeline to generate a protein localization atlas at the nanoscale level for about 30 muscle proteins, and to provide a refined molecular model of the sarcomeric I-band and H-zone of the adult Drosophila IFM [ 39 ].…”

Filamin protects myofibrils from contractile damage through changes in its mechanosensory region

“…Moreover, filamin is observed to accumulate at myofibril microlesions that occur during intense muscle contractions induced by either forced exercise or electrical stimulation [ 10 , 12 , 19 ]. Utilizing single-molecule localization microscopy, it has been revealed that filamin’s actin-binding domains are centrally located within the Z-disc, while the dimerization domains are positioned at the periphery of the disc [ 23 , 42 ], providing an ideal arrangement for sensing Z-disc deformation caused by muscle contractions [ 22 ]. All these experimental data have led to the hypothesis that filamin senses mechanical damage at the Z-disc where it coordinates a compensatory stabilization mechanism that prevents the Z-disc from rupturing.…”

Filamin protects myofibrils from contractile damage through changes in its mechanosensory region

“…Moreover, filamin is observed to accumulate at myofibril microlesions that occur during intense muscle contractions induced by either forced exercise or electrical stimulation [9][10][15]. Utilizing single-molecule localization microscopy, it has been revealed that filamin’s actin-binding domains are centrally located within the Z-disc, while the dimerization domains are positioned at the periphery of the disc [19,38], providing an ideal arrangement for sensing Z-disc deformation caused by muscle contractions [18]. All these experimental data have led to the hypothesis that filamin senses mechanical damage at the Z-disc where it coordinates myofibril repair.…”