Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/52754
Title: Differential pattern of glycogen accumulation after protein phosphatase 1 glycogen-targeting subunit PPP1R6 overexpression, compared to PPP1R3C and PPP1R3A, in skeletal muscle cells
Author: Montori Grau, Marta
Guitart de la Rosa, Maria
García Martínez, Celia
Orozco, Anna
Gómez Foix, Anna Maria
Keywords: Regulació del metabolisme
Regulació genètica
Expressió gènica
Aparell locomotor
Metabolisme
Glicogen
Fetge
Àcids grassos
Metabolic regulation
Genetic regulation
Gene expression
Musculoskeletal system
Metabolism
Glycogen
Liver
Fatty acids
Issue Date: 4-Nov-2011
Publisher: BioMed Central
Abstract: Background PPP1R6 is a protein phosphatase 1 glycogen-targeting subunit (PP1-GTS) abundant in skeletal muscle with an undefined metabolic control role. Here PPP1R6 effects on myotube glycogen metabolism, particle size and subcellular distribution are examined and compared with PPP1R3C/PTG and PPP1R3A/GM. Results PPP1R6 overexpression activates glycogen synthase (GS), reduces its phosphorylation at Ser-641/0 and increases the extracted and cytochemically-stained glycogen content, less than PTG but more than GM. PPP1R6 does not change glycogen phosphorylase activity. All tested PP1-GTS-cells have more glycogen particles than controls as found by electron microscopy of myotube sections. Glycogen particle size is distributed for all cell-types in a continuous range, but PPP1R6 forms smaller particles (mean diameter 14.4 nm) than PTG (36.9 nm) and GM (28.3 nm) or those in control cells (29.2 nm). Both PPP1R6- and GM-derived glycogen particles are in cytosol associated with cellular structures; PTG-derived glycogen is found in membrane- and organelle-devoid cytosolic glycogen-rich areas; and glycogen particles are dispersed in the cytosol in control cells. A tagged PPP1R6 protein at the C-terminus with EGFP shows a diffuse cytosol pattern in glucose-replete and -depleted cells and a punctuate pattern surrounding the nucleus in glucose-depleted cells, which colocates with RFP tagged with the Golgi targeting domain of β-1,4-galactosyltransferase, according to a computational prediction for PPP1R6 Golgi location. Conclusions PPP1R6 exerts a powerful glycogenic effect in cultured muscle cells, more than GM and less than PTG. PPP1R6 protein translocates from a Golgi to cytosolic location in response to glucose. The molecular size and subcellular location of myotube glycogen particles is determined by the PPP1R6, PTG and GM scaffolding.
Note: Reproducció del document publicat a: http://dx.doi.org/10.1186/1471-2091-12-57
It is part of: BMC Biochemistry, 2011, vol. 12, num. 57
Related resource: http://dx.doi.org/10.1186/1471-2091-12-57
URI: http://hdl.handle.net/2445/52754
ISSN: 1471-2091
Appears in Collections:Articles publicats en revistes (Bioquímica i Biomedicina Molecular)
Articles publicats en revistes (Patologia i Terapèutica Experimental)

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