Anne Osterrieder, Imogen A Sparkes, Stan W Botchway, Andy Ward, Tijs Ketelaar, Norbert de Ruijter, Chris Hawes
The plant Golgi apparatus modifies and sorts incoming proteins from the endoplasmic reticulum (ER) and synthesizes cell wall matrix material. Plant cells possess numerous motile Golgi bodies, which are connected to the ER by yet to be identified tethering factors. Previous studies indicated a role for cis-Golgi plant golgins, which are long coiled-coil domain proteins anchored to Golgi membranes, in Golgi biogenesis. Here we show a tethering role for the golgin AtCASP at the ER-Golgi interface. Using live-cell imaging, Golgi body dynamics were compared in Arabidopsis thaliana leaf epidermal cells expressing fluorescently tagged AtCASP, a truncated AtCASP-ΔCC lacking the coiled-coil domains, and the Golgi marker STtmd. Golgi body speed and displacement were significantly reduced in AtCASP-ΔCC lines. Using a dual-colour optical trapping system and a TIRF-tweezer system, individual Golgi bodies were captured in planta. Golgi bodies in AtCASP-ΔCC lines were easier to trap and the ER-Golgi connection was more easily disrupted. Occasionally, the ER tubule followed a trapped Golgi body with a gap, indicating the presence of other tethering factors. Our work confirms that the intimate ER-Golgi association can be disrupted or weakened by expression of truncated AtCASP-ΔCC and suggests that this connection is most likely maintained by a golgin-mediated tethering complex.
DOI
Showing posts with label Journal of Experimental Botany. Show all posts
Showing posts with label Journal of Experimental Botany. Show all posts
Thursday, September 21, 2017
Endoplasmic reticulum and Golgi apparatus: old friends, novel intimate relationships
Alessandro Vitale, Emanuela Pedrazzini
The mid-nineteen century invention of subcellular fractionation and the application of electron microscopy to cell biology allowed us to discover the functional connections between the endoplasmic reticulum (ER) and Golgi apparatus in protein synthesis and secretion. This progress – which formed part of those steps forward resulting in the Nobel Prize for Physiology or Medicine in 1974 to Albert Claude, Christian de Duve and George Palade – opened the way to the discovery of intracellular membrane trafficking, the diverse compartments of the endomembrane system, and the secretory and endocytic pathways. The biosynthetic branch of the secretory pathway starts from the ER and leads to the Golgi apparatus as the first intermediate station. At the end of last century, the discovery of vesicle budding and fusion together with associated protein machinery, the continued refinement of electron microscopy, and the development of confocal microscopy and fluorescent protein tags – combining recombinant DNA and live imaging – have opened an intense and still-ongoing debate about the mechanistic aspects of the functional connections between compartments (Spang, 2013; Robinson et al., 2015). This is particularly important at ER exit, where thousands of proteins destined for secretion or different endomembrane compartments start their life.
DOI
The mid-nineteen century invention of subcellular fractionation and the application of electron microscopy to cell biology allowed us to discover the functional connections between the endoplasmic reticulum (ER) and Golgi apparatus in protein synthesis and secretion. This progress – which formed part of those steps forward resulting in the Nobel Prize for Physiology or Medicine in 1974 to Albert Claude, Christian de Duve and George Palade – opened the way to the discovery of intracellular membrane trafficking, the diverse compartments of the endomembrane system, and the secretory and endocytic pathways. The biosynthetic branch of the secretory pathway starts from the ER and leads to the Golgi apparatus as the first intermediate station. At the end of last century, the discovery of vesicle budding and fusion together with associated protein machinery, the continued refinement of electron microscopy, and the development of confocal microscopy and fluorescent protein tags – combining recombinant DNA and live imaging – have opened an intense and still-ongoing debate about the mechanistic aspects of the functional connections between compartments (Spang, 2013; Robinson et al., 2015). This is particularly important at ER exit, where thousands of proteins destined for secretion or different endomembrane compartments start their life.
DOI
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