RT Journal Article
T1 The yeast cell wall integrity pathway signals from recycling endosomes upon elimination of phosphatidylinositol (4,5)-bisphosphate by mammalian phosphatidylinositol 3-kinase.
A1 Fernández Acero, Teresa
A1 Rodríguez Escudero, Isabel
A1 Molina, María
A1 Cid, Víctor J.
AB Phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2] is essential for recognition of the plasma membrane inner leaf by protein complexes. We expressed mammalian class I phosphoinositide 3-kinase (PI3K) in Saccharomyces cerevisiae to eliminate PtdIns(4,5)P2 by its conversion into PtdIns(3,4,5)P3, a lipid naturally missing in this yeast. This led to loss of actin function and endocytosis defects, causing a blockage in polarized secretion. Also, the cell wall integrity (CWI) mitogen-activated protein kinase (MAPK) pathway was activated, triggering a typical transcriptional response. In the absence of PtdIns(4,5)P2 at the plasma membrane, the Pkc1 protein kinase upstream the CWI MAPK module localized to post-Golgi endosomes marked by SNARE Snc1 and Rab GTPases Ypt31 and Ypt32. Other components at the head of the pathway, like the mechanosensor Wsc1, the GTPase Rho1 and its activator the GDP/GTP exchange factor Rom2, co-localized with Pkc1 in these compartments. Chemical inhibition of PI3K proved that both CWI activation and Pkc1 relocation to endosomes are reversible. These results suggest that the CWI pathway is able to respond to loss of plasma membrane identity from recycling endosomes.
PB Elsevier
SN 0898-6568
YR 2015
FD 2015-08-07
LK https://hdl.handle.net/20.500.14352/24211
UL https://hdl.handle.net/20.500.14352/24211
LA eng
NO Ministerio de Ciencia e Innovación (MICINN)
NO Ministerio de Ciencia y Competitividad (MINECO)
NO Comunidad Autónoma de Madrid
DS Docta Complutense
RD 6 may 2024