Related Experiment Video
Updated: Mar 21, 2026

Understanding the Changes in Mitochondrial Morphology through Dynamic and Three-dimensional Fluorescence Micrographs
Published on: August 15, 2025
The ceramide-activated protein phosphatase Sit4p controls lifespan, mitochondrial function and cell cycle progression
António Daniel Barbosa1,2, Clara Pereira3,1, Hugo Osório3,4
1b IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto , Porto , Portugal.
Abstract:
Sit4p is the catalytic subunit of a ceramide-activated PP2A-like phosphatase that regulates cell cycle, mitochondrial function, oxidative stress resistance and chronological lifespan in yeast. In this study, we show that hexokinase 2 (Hxk2p) is hyperphosphorylated in sit4Δ mutants grown in glucose medium by a Snf1p-independent mechanism and Hxk2p-S15A mutation suppresses phenotypes associated with SIT4 deletion, namely growth arrest at G1 phase, derepression of mitochondrial respiration, H2O2 resistance and lifespan extension. Consistently, the activation of Sit4p in isc1Δ mutants, which has been associated with premature aging, leads to Hxk2p hypophosphorylation, and the expression of Hxk2p-S15E increases the lifespan of isc1Δ cells. The overall results suggest that Hxk2p functions downstream of Sit4p in the control of cell cycle, mitochondrial function, oxidative stress resistance and chronological lifespan.
More Related Videos
10:39A Suppressor Screen for the Characterization of Genetic Links Regulating Chronological Lifespan in Saccharomyces cerevisiae
Published on: September 17, 2020
13:15Experimental Approaches to Study Mitochondrial Localization and Function of a Nuclear Cell Cycle Kinase, Cdk1
Published on: February 25, 2016
Related Concept Videos
PI3K/mTOR/AKT Signaling Pathway
Inhibition of Cdk Activity
Cells Coordinate Growth and Proliferation
Positive Regulator Molecules
Positive Regulator Molecules
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...