Reverse fountain flow of phosphatidylinositol‐3,4‐bisphosphate polarizes migrating cells

Abstract

The ability of cells to polarize and move toward external stimuli plays a crucial role in development, as well as in normal and pathological physiology. Migrating cells maintain dynamic complementary distributions of Ras activity and of the phospholipid phosphatidylinositol‐3,4‐bisphosphate (PI(3,4)P2). Here, we show that lagging‐edge component PI(3,4)P2 also localizes to retracting leading‐edge protrusions and nascent macropinosomes, even in the absence of phosphatidylinositol 3,4,5‐trisphosphate (PIP3). Once internalized, macropinosomes break up into smaller PI(3,4)P2‐enriched vesicles, which fuse with the plasma membrane at the rear of the cell. Subsequently, the phosphoinositide diffuses toward the front of the cell, where it is degraded. Computational modeling confirms that this cycle gives rise to stable back‐to‐front gradient. These results uncover a surprising “reverse‐fountain flow” of PI(3,4)P2 that regulates polarity.

Optogenetic modulation of guanine nucleotide exchange factors of Ras superfamily proteins directly controls cell shape and movement

“…For stable protein expression in HL-60 cells, a combination of lentiviral and transposon approaches was used sequentially ( Bell et al, 2021 ; Hadjitheodorou et al, 2021 ; Li et al, 2021 ; Pal et al, 2023 ). The procedure involved three steps.…”

“…Dictyostelium stable cell lines were generated by electroporation ( Li et al, 2021 ; Banerjee et al, 2022 ; Banerjee et al, 2023 ; Pal et al, 2023 ). Briefly, 1 × 10 7 cells were harvested, washed twice, and resuspended in 100 μL ice-cold H-50 buffer.…”

Direct activation of the Ras-Akt network mediates polarity and organizes protrusions in human neutrophil migration

“…Stable expression lines in HL-60 cells were generated by a combination of 3 rd -generation lentiviral- and PiggyBac™ transposon-integration based approaches 18, 132 . Virus was prepared in HEK293T cells grown to ∼80% confluency in 10 cm cell culture dish (Greiner Bio-One; 664160).…”

Moving the Research Forward: The Best of British Biology Using the Tractable Model System Dictyostelium discoideum

“…Due to the visualisation of both the dynamics of the chemotactic signals and the resulting chemotactic response and interactions between them during all stages of development, it has been possible to classify Dictyostelium morphogenesis as a highly self-organised process based on two essential cell behaviours: excitable cell-cell signalling and chemotaxis, resulting in robust multicellular morphogenesis [78]. Many questions remain to be resolved regarding the detailed molecular mechanisms associated with cell polarisation and cytoskeletal dynamics during the chemotactic response and the role of cell contact in cell polarisation in the later stages of development [79][80][81][82]. Due to the visualisation of both the dynamics of the chemotactic signals and the resulting chemotactic response and interactions between them during all stages of development, it has been possible to classify Dictyostelium morphogenesis as a highly self-organised process based on two essential cell behaviours: excitable cell-cell signalling and chemotaxis, resulting in robust multicellular morphogenesis [78].…”

“…Due to the visualisation of both the dynamics of the chemotactic signals and the resulting chemotactic response and interactions between them during all stages of development, it has been possible to classify Dictyostelium morphogenesis as a highly self-organised process based on two essential cell behaviours: excitable cell–cell signalling and chemotaxis, resulting in robust multicellular morphogenesis [ 78 ]. Many questions remain to be resolved regarding the detailed molecular mechanisms associated with cell polarisation and cytoskeletal dynamics during the chemotactic response and the role of cell contact in cell polarisation in the later stages of development [ 79 , 80 , 81 , 82 ].…”