Related Experiment Video
Updated: Nov 25, 2025
08:55
Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae
Published on: July 19, 2021
3.2K
Mitochondrial Localization of the Yeast Forkhead Factor Hcm1
María José Rodríguez Colman1, Joaquim Ros1, Elisa Cabiscol1
1Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
International Journal of Molecular Sciences
|December 19, 2020
Summary
Hcm1, a forkhead transcription factor, accumulates in the nucleus during G1/S and translocates to mitochondria during G2/M. This suggests Hcm1 regulates mitochondrial gene expression, impacting cellular metabolism.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Hcm1 is a forkhead transcription factor in Saccharomyces cerevisiae.
- Hcm1 plays roles in cell division and mitochondrial biogenesis.
- Hcm1 activity is regulated by protein levels, localization, and transcriptional activity.
Purpose of the Study:
- To investigate the cell cycle-dependent localization and function of Hcm1.
- To determine if Hcm1 has a role in mitochondrial gene expression.
Main Methods:
- Cell cycle analysis of Hcm1 protein levels and localization.
- Mitochondrial purification using sucrose gradient density centrifugation.
- Analysis of Hcm1 colocalization with mitochondrial markers.
- Measurement of COX1 gene expression.
Main Results:
- Hcm1 protein levels increase and accumulate in the nucleus during G1/S.
- Hcm1 decreases and localizes to a network outside the nucleus during G2/M.
- Purified mitochondria show Hcm1 colocalization with mitochondrial markers.
- Hcm1 induces expression of COX1, a mitochondrial-encoded gene, during G2/M.
Conclusions:
- Hcm1 exhibits cell cycle-dependent nuclear and mitochondrial localization.
- Hcm1 functions as a mitochondrial transcription factor, regulating COX1 expression.
- These findings reveal a novel role for Hcm1 in mitochondrial metabolism.
Related Concept Videos
01:39Mitochondrial Protein Sorting
5.3K
Mitochondria are double-membrane organelles of the eukaryotes involved in cellular metabolism, signaling, ATP synthesis, and programmed cell death. Each of these processes requires specific proteins and enzymes that must be correctly sorted to the right mitochondrial subcompartment for the proper functioning of the organelle.
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
5.3K
01:19Translocation of Proteins into the Mitochondria
10.3K
Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
10.3K
02:30Histone Variants at the Centromere
4.7K
Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3...
4.7K
01:39Mitochondrial Precursor Proteins
3.3K
Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70 chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial...
Most of the mitochondrial...
3.3K
01:37Energy to Drive Translocation
2.5K
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
2.5K
01:12Porin Insertion in the Outer Mitochondrial Membrane
4.0K
Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
4.0K