Endosomal cargo recycling mediated by Gpa1 and phosphatidylinositol 3-kinase is inhibited by glucose starvation

TY - JOUR

T1 - Endosomal cargo recycling mediated by Gpa1 and phosphatidylinositol 3-kinase is inhibited by glucose starvation

AU - Laidlaw, Kamilla M E

AU - Paine, Katherine M

AU - Bisinski, Daniel D

AU - Calder, Grant

AU - Hogg, Karen

AU - Ahmed, Sophia

AU - James, Sally

AU - O'Toole, Peter J

AU - MacDonald, Chris

N1 - © 2022 Laidlaw, Paine, et al.

PY - 2022/4/1

Y1 - 2022/4/1

N2 - Cell surface protein trafficking is regulated in response to nutrient availability, with multiple pathways directing surface membrane proteins to the lysosome for degradation in response to suboptimal extracellular nutrients. Internalized protein and lipid cargoes recycle back to the surface efficiently in glucose-replete conditions, but this trafficking is attenuated following glucose starvation. We find that cells with either reduced or hyperactive phosphatidylinositol 3-kinase (PI3K) activity are defective for endosome to surface recycling. Furthermore, we find that the yeast Gα subunit Gpa1, an endosomal PI3K effector, is required for surface recycling of cargoes. Following glucose starvation, mRNA and protein levels of a distinct Gα subunit Gpa2 are elevated following nuclear translocation of Mig1, which inhibits recycling of various cargoes. As Gpa1 and Gpa2 interact at the surface where Gpa2 concentrates during glucose starvation, we propose that this disrupts PI3K activity required for recycling, potentially diverting Gpa1 to the surface and interfering with its endosomal role in recycling. In support of this model, glucose starvation and overexpression of Gpa2 alter PI3K endosomal phosphoinositide production. Glucose deprivation therefore triggers a survival mechanism to increase retention of surface cargoes in endosomes and promote their lysosomal degradation.

AB - Cell surface protein trafficking is regulated in response to nutrient availability, with multiple pathways directing surface membrane proteins to the lysosome for degradation in response to suboptimal extracellular nutrients. Internalized protein and lipid cargoes recycle back to the surface efficiently in glucose-replete conditions, but this trafficking is attenuated following glucose starvation. We find that cells with either reduced or hyperactive phosphatidylinositol 3-kinase (PI3K) activity are defective for endosome to surface recycling. Furthermore, we find that the yeast Gα subunit Gpa1, an endosomal PI3K effector, is required for surface recycling of cargoes. Following glucose starvation, mRNA and protein levels of a distinct Gα subunit Gpa2 are elevated following nuclear translocation of Mig1, which inhibits recycling of various cargoes. As Gpa1 and Gpa2 interact at the surface where Gpa2 concentrates during glucose starvation, we propose that this disrupts PI3K activity required for recycling, potentially diverting Gpa1 to the surface and interfering with its endosomal role in recycling. In support of this model, glucose starvation and overexpression of Gpa2 alter PI3K endosomal phosphoinositide production. Glucose deprivation therefore triggers a survival mechanism to increase retention of surface cargoes in endosomes and promote their lysosomal degradation.

KW - Endosomes/metabolism

KW - GTP-Binding Protein alpha Subunits/genetics

KW - Glucose/metabolism

KW - Membrane Proteins/metabolism

KW - Phosphatidylinositol 3-Kinase/metabolism

KW - Phosphatidylinositol 3-Kinases/metabolism

KW - Protein Transport

KW - Saccharomyces cerevisiae/metabolism

KW - Saccharomyces cerevisiae Proteins/metabolism

U2 - 10.1091/mbc.E21-04-0163

DO - 10.1091/mbc.E21-04-0163

M3 - Article

C2 - 35080991

SN - 1059-1524

VL - 33

JO - Molecular Biology of the Cell

JF - Molecular Biology of the Cell

IS - 4

M1 - ar31

ER -