Subcellular shifts of trimeric G-proteins following activation of baker's yeast by glucose.
Addition of glucose to a resting cell suspension of the yeast Saccharomyces cerevisiae was accompanied by marked shifts of the G alpha-protein subunits from the plasma membrane to the cell interior. This process was rapid with half-times between < 10 and 20 s. The decrease of the plasma membrane pool of the Gi alpha/Go alpha- and Gq alpha/Gl 1 alpha-protein subunits correlated with an increase in acid-sensitive forms of these proteins which was recovered in the mitochondrial and/or lysosomal membrane fraction. In contrast to cells from higher organisms glucose-stimulated yeast exhibits an extremely rapid type of the redistribution (internalization). The question remains open as to the functional significance of the internalized forms of the G-proteins as these remain sequestered from the plasma membrane well after glucose has been consumed.
Kotyk
A
A
Department of Membrane Transport, Institute of Physiology, Academy of Sciences of the Czech Republic, 142 20 Prague, Czechia. kotyk@biomed.cas.cz
Ihnatovych
I
I
Lapathitis
G
G
Lamash
N
N
Svoboda
P
P
D019204:GTP-Binding Proteins / Q000032:analysis / Q000096:biosynthesis*; D005947:Glucose / Q000494:pharmacology*; D015151:Immunoblotting; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
D019204:GTP-Binding Proteins; D005947:Glucose