Microtubule assembly in meiotic extract requires glycogen

Abstract

We identified a clarified extract containing the soluble factors for microtubule assembly. We found that microtubule assembly does not require ribosomes, mitochondria, or membranes. Our clarified extracts will provide a powerful tool for activity-based biochemical fractionations for microtubule assembly.

Interplay Between Spindle Architecture and Function

“…Across eukaryotic biology, cell size and shape vary dramatically, requiring complex spatial information to be integrated by the spindle, which may adjust by altering spindle factors and their organization. Genomewide screening and proteomic studies have provided comprehensive lists of spindle-associated proteins and there is evidence that nonprotein components other than chromosomes such as RNA also function as integral spindle components (Blower et al, 2005;Bonner et al, 2011;Chang et al, 2004;Gache et al, 2010;Goshima et al, 2007;Groen et al, 2011). Together with functional investigation of individual factors, these studies provide a critical foundation for investigating the physiological mechanisms that tune spindle size, morphology, and function.…”

“…These are RNA, poly-ADP ribose, and glycogen (Blower et al, 2005;Chang et al, 2004;Groen et al, 2011). While the molecular mechanisms by which these factors act to promote spindle 114 Kara J.…”

Self-organization of stabilized microtubules by both spindle and midzone mechanisms inXenopusegg cytosol

“…We recently reported this preparation as part of an effort to biochemically reconstitute microtubule nucleation stimulated by Ran.GTP (Groen et al ., 2011). A key innovation was to supplement cytosol with glycogen, which is naturally present at ∼30 mg/ml in egg cytoplasm.…”

Fueled by microtubules: Does tubulin dimer/polymer partitioning regulate intracellular metabolism?

“…Thus, expression of some VHL mutants could lead to shifts in tubulin partitioning between dimer and polymer pools, which may then inhibit expression of glycolytic enzymes and GLUTs. Finally, glycogen, a storage form of glucose, is required for MT assembly in Xenopus meiotic egg extracts [Groen et al, 2011], again highlighting possible connections between metabolism and MT dynamics.…”

“…Thus, expression of some VHL mutants could lead to shifts in tubulin partitioning between dimer and polymer pools, which may then inhibit expression of glycolytic enzymes and GLUTs. Finally, glycogen, a storage form of glucose, is required for MT assembly in Xenopus meiotic egg extracts [Groen et al, 2011], again highlighting possible connections between metabolism and MT dynamics.Disruption of metabolic pathways should be reflected in increased AMP and decreased ATP levels. This shift in nucleotide ratio between AMP and ATP will activate AMPK, a kinase that is responsible for sensing energy availability and serving as a master regulator of metabolic processes to maintain ATP levels.…”