Article

Regulation of distinct septin rings in a single cell by Elm1p and Gin4p kinases.

Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA.
Molecular biology of the cell (impact factor: 5.98). 03/2009; 20(8):2311-26. DOI:10.1091/mbc.E08-12-1169 pp.2311-26
Source: PubMed

ABSTRACT Septins are conserved, GTP-binding proteins that assemble into higher order structures, including filaments and rings with varied cellular functions. Using four-dimensional quantitative fluorescence microscopy of Ashbya gossypii fungal cells, we show that septins can assemble into morphologically distinct classes of rings that vary in dimensions, intensities, and positions within a single cell. Notably, these different classes coexist and persist for extended times, similar in appearance and behavior to septins in mammalian neurons and cultured cells. We demonstrate that new septin proteins can add through time to assembled rings, indicating that septins may continue to polymerize during ring maturation. Different classes of rings do not arise from the presence or absence of specific septin subunits and ring maintenance does not require the actin and microtubule cytoskeletons. Instead, morphological and behavioral differences in the rings require the Elm1p and Gin4p kinases. This work demonstrates that distinct higher order septin structures form within one cell because of the action of specific kinases.

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Keywords

Ashbya gossypii fungal cells
 
behavioral differences
 
cultured cells
 
Different classes
 
different classes coexist
 
dimensions
 
Elm1p
 
filaments
 
four-dimensional quantitative fluorescence microscopy
 
GTP-binding proteins
 
mammalian neurons
 
microtubule cytoskeletons
 
morphologically distinct classes
 
new septin proteins
 
polymerize
 
septins
 
single cell
 
specific septin subunits
 
times
 
varied cellular functions
 

Bradley S Demay