Imaging membrane remodeling during regulated exocytosis in live mice

Abstract

In this mini-review we focus on the use of time-lapse light microscopy to study membrane remodeling during protein secretion in live animals. In particular, we highlight how subcellular intravital microscopy has enabled imaging the dynamics of both individual secretory vesicles and the plasma membrane, during different steps in the exocytic process. This powerful approach has provided us with the unique opportunity to unravel the role of the actin cytoskeleton in regulating this process under physiological conditions, and to overcome the shortcomings of more reductionist model systems.

Complexity of the Nano-Bio Interface and the Tortuous Path of Metal Oxides in Biological Systems

“…In this case, cargo proteins are synthesized when needed by the cell and packaged into granules for subsequent release. Regulated exocytosis occurs in hematopoietic, neuronal, endocrine and exocrine cells [ 152 ]. Interactions among the elemental composition, size, shape, surface characteristics, and cell type fully as complex as interactions affecting uptake also affect NP exocytosis [ 153 ].…”

Concerted actions of distinct nonmuscle myosin II isoforms drive intracellular membrane remodeling in live animals

“…The forces are provided by cytoplasmic protein complexes ( Daley and Yamada, 2013 ; Henne et al, 2013 ; Simunovic and Bassereau, 2014 ), which include curvature generators such as BAR (Bin/Amphiphysin/Rvs) domain–containing proteins ( Kozlov et al, 2014 ; Suetsugu et al, 2014 ), the ESCRT (endosomal sorting complexes required for transport) complex ( Henne et al, 2013 ; Chiaruttini et al, 2015 ), fission factors such as the large GTPase dynamin ( Ferguson and De Camilli, 2012 ), and various components of the actomyosin cytoskeleton ( Hatch et al, 2014 ; Korobova et al, 2014 ). Although membrane remodeling has been extensively studied in cell-free systems and cultured cells, information about the dynamics, mechanisms, and molecular players that drive and regulate this process in multicellular organisms in vivo, where the three-dimensional architecture, cell–cell interactions, and cues coming from vasculature and nervous systems likely have key effects ( Shitara and Weigert, 2015 ), remains sparse. To address this, we established an in vivo model system to study the role of the actomyosin cytoskeleton in membrane remodeling during regulated exocytosis, a fundamental process in secretory organs ( Burgoyne and Morgan, 2003 ; Sokac et al, 2003 ; Jerdeva et al, 2005 ; Nightingale et al, 2011 ; Miklavc et al, 2012 ; Porat-Shliom et al, 2013 ).…”

In vivo imaging of skeletal muscle in mice highlights muscle defects in a model of myotubular myopathy

“…A few studies previously reported in vivo microscopy of skeletal muscle. 26,27 While some disease hallmarks can be recapitulated in vitro, intravital imaging (IVM) offers a window to the progression of the disease, and its associated cellular events such as subcellular membrane trafficking, 28 in a living animal. [29][30][31] Owing to its superior imaging property and its compatibility with non-linear optical processes, Two-Photon-Excitation-Microscopy (2PEM) allows simultaneous tracking of fluorescent events in vivo as well as detection of non-centrosymetric molecules by second harmonic generation (SHG) such as myosin in muscle, 32 and collagen in the extracellular matrix.…”