Mechanisms of Intracellular Scaling

Abstract

Cell size varies widely among different organisms as well as within the same organism in different tissue types and during development, which places variable metabolic and functional demands on organelles and internal structures. A fundamental question is how essential subcellular components scale to accommodate cell size differences. Nuclear transport has emerged as a conserved means of scaling nuclear size. A meiotic spindle scaling factor has been identified as the microtubule-severing protein katanin, which is differentially regulated by phosphorylation in two different-sized frog species. Anaphase mechanisms and levels of chromatin compaction both act to coordinate cell size with spindle and chromosome dimensions to ensure accurate genome distribution during cell division. Scaling relationships and mechanisms for many membrane-bound compartments remain largely unknown and are complicated by their heterogeneity and dynamic nature. This review summarizes cell and organelle size relationships and the experimental approaches that have elucidated mechanisms of intracellular scaling.

Manipulation of Karyotype inCaenorhabditis elegansReveals Multiple Inputs Driving Pairwise Chromosome Synapsis During Meiosis

“…The strategy described here could also prove to be a valuable tool to interrogate processes relevant to cell and genome biology, physiology, or development in a model animal. For example, analyzing how the cell and its components, such as the nucleus or mitotic spindle, scale in response to an increase in DNA content may enable interrogation of the genetic circuits responsible for such scaling (Levy and Heald 2012). Further, polyploid strains may be useful for investigating the mechanisms that regulate endoreplication in tissues in which cells are normally polyploid (Hedgecock and White 1985;Lozano et al 2006).…”

Mechanisms and mechanics of cell competition in epithelia

“…As this boundary is characterized by increased junctional tension 84 , it could act as a mechanical insulator, thus preventing transmission of the strains caused by inhomogeneous growth. Mechanical influences could also explain how cells, such as cancer cells, that acquire extra DNA or chromosomes could become super-competitors, as these cells tend to increase in size as a result of hyperploidy 85 . The importance of spatial constraints has also been recently highlighted in a recent report showing that post-mitotic epithelial cells increase in size to fill the void caused by tissue injury (that is, compensatory cellular hypertrophy) 40 .…”

Golgi enlargement in Arf-depleted yeast cells is due to altered dynamics of cisternal maturation

“…The mechanisms that control organelle size and number are attracting increasing interest (Goehring and Hyman, 2012;Levy and Heald, 2012;Marshall, 2002;Sengupta and Linstedt, 2011). Apart from being a basic cell biological problem, this topic has clinical relevance because cancer cells display altered organelle structure (Levy and Heald, 2012;Zink et al, 2004).…”