TY - JOUR
T1 - The stress-activated phosphatidylinositol 3-phosphate 5-kinase Fab1p is essential for vacuole function in S. cerevisiae
AU - Cooke, Frank T.
AU - Dove, Stephen K.
AU - McEwen, Robert K.
AU - Painter, Gavin
AU - Holmes, Andrew B.
AU - Hall, Michael N.
AU - Michell, Robert H.
AU - Parker, Peter J.
PY - 1998/11/5
Y1 - 1998/11/5
N2 - Polyphosphoinositides have many roles in cell signalling and vesicle trafficking. Phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2), a recently discovered PIP2 isomer, is ubiquitous in eukaryotic cells and rapidly accumulates in hyperosmotically stressed yeast. PI(3,5)P2 is synthesised from PI(3)P in both yeast and mammalian cells. A search of the Saccharomyces cerevisiae genome database identified FAB1, a gene encoding a PIP kinase homologue and potential PI(3)P 5-kinase. Fab1p shows PI(3)P 5-kinase activity both in vivo and in vitro. A yeast strain in which FAB1 had been deleted was unable to synthesise PI(3,5)P2, either in the presence or absence of osmotic shock. A loss of PI(3,5)P2 was observed also in a temperature-sensitive FAB1 strain at the non-permissive temperature. A recombinant glutathione-S-transferase (GST)-Fab1p fusion protein was shown to have selective PI(3)P 5-kinase activity in vitro. Thus, we have demonstrated that Fab1p is a PI(3)P-specific 5-kinase and represents a third class of PIP kinase activity, which we have termed type III. Deletion of the FAB1 gene produces a loss of vacuolar morphology; it is therefore concluded that PI(3,5)P2, the lipid product of Fab1p, is required for normal vacuolar function.
AB - Polyphosphoinositides have many roles in cell signalling and vesicle trafficking. Phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2), a recently discovered PIP2 isomer, is ubiquitous in eukaryotic cells and rapidly accumulates in hyperosmotically stressed yeast. PI(3,5)P2 is synthesised from PI(3)P in both yeast and mammalian cells. A search of the Saccharomyces cerevisiae genome database identified FAB1, a gene encoding a PIP kinase homologue and potential PI(3)P 5-kinase. Fab1p shows PI(3)P 5-kinase activity both in vivo and in vitro. A yeast strain in which FAB1 had been deleted was unable to synthesise PI(3,5)P2, either in the presence or absence of osmotic shock. A loss of PI(3,5)P2 was observed also in a temperature-sensitive FAB1 strain at the non-permissive temperature. A recombinant glutathione-S-transferase (GST)-Fab1p fusion protein was shown to have selective PI(3)P 5-kinase activity in vitro. Thus, we have demonstrated that Fab1p is a PI(3)P-specific 5-kinase and represents a third class of PIP kinase activity, which we have termed type III. Deletion of the FAB1 gene produces a loss of vacuolar morphology; it is therefore concluded that PI(3,5)P2, the lipid product of Fab1p, is required for normal vacuolar function.
UR - http://www.scopus.com/inward/record.url?scp=0032488032&partnerID=8YFLogxK
U2 - 10.1016/s0960-9822(07)00513-1
DO - 10.1016/s0960-9822(07)00513-1
M3 - Article
C2 - 9811604
AN - SCOPUS:0032488032
SN - 0960-9822
VL - 8
SP - 1219
EP - 1222
JO - Current Biology
JF - Current Biology
IS - 22
ER -