Related Experiment Video

Updated: Dec 7, 2025

Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae
08:55

Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae

Published on: July 19, 2021

3.2K

Yeast homologs of human MCUR1 regulate mitochondrial proline metabolism

Mohammad Zulkifli1, John K Neff1, Shrishiv A Timbalia1

  • 1Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.

Nature Communications
|September 26, 2020
PubMed

Insights

Researchers discovered that MCUR1 homologs, Put6 and Put7, regulate mitochondrial proline metabolism in yeast. Loss of these proteins disrupts proline utilization and cellular redox balance, revealing a novel function for MCUR1 in metabolic pathways.

Area of Science:

  • Cellular Biology
  • Biochemistry
  • Mitochondrial Biology

Background:

  • Mitochondria are central to cellular energy production via carbon and nitrogen metabolism.
  • Mitochondrial calcium uptake, regulated by the mitochondrial calcium uniporter (MCU) complex, is crucial for bioenergetics.
  • The scaffold factor MCUR1 facilitates MCU complex assembly, but its homologs in fungi lacking MCU suggest alternative roles.

Purpose of the Study:

  • To investigate the function of Saccharomyces cerevisiae MCUR1 homologs, Put6 and Put7.
  • To determine the role of Put6 and Put7 in mitochondrial proline metabolism and homeostasis.
  • To elucidate the relationship between MCUR1 homologs, proline metabolism, and cellular redox balance.

Main Methods:

  • Characterization of Put6 and Put7 as MCUR1 homologs in yeast.
  • Analysis of Put6 and Put7 localization and complex formation in the inner mitochondrial membrane.
  • Assessment of proline utilization and cellular redox balance in yeast strains lacking Put6 or Put7.
  • Complementation studies using heterologous expression of human MCUR1.

Main Results:

  • Put6 and Put7 form a large hetero-oligomeric complex tethered to the inner mitochondrial membrane, regulated by proline abundance.
  • Loss of Put6 or Put7 leads to impaired mitochondrial proline homeostasis and disrupted cellular redox balance.
  • Yeast cells deficient in Put6 or Put7 show significant defects in proline utilization.
  • Heterologous expression of human MCUR1 rescues the proline utilization defect in yeast lacking Put6 or Put7.

Conclusions:

  • MCUR1 homologs Put6 and Put7 function as key regulators of mitochondrial proline metabolism in yeast.
  • This study reveals a novel, non-canonical role for MCUR1 homologs in managing proline homeostasis and cellular redox state.
  • The findings suggest that MCUR1-related proteins have conserved, yet diverse, functions in metabolic regulation across species.

More Related Videos

Author Spotlight: Advancing Techniques and Discoveries in Protein Synthesis and Assembly Through Innovative Mitochondrial Research09:53

Author Spotlight: Advancing Techniques and Discoveries in Protein Synthesis and Assembly Through Innovative Mitochondrial Research

Published on: June 7, 2024

1.4K
Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe08:07

Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe

Published on: May 2, 2025

759

Related Concept Videos

Mitochondrial Protein Sorting01:39

Mitochondrial Protein Sorting

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...
5.4K
Mitochondrial Precursor Proteins01:39

Mitochondrial Precursor Proteins

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...
3.3K
Translocation of Proteins into the Mitochondria01:19

Translocation of Proteins into the Mitochondria

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,...
10.9K
Porin Insertion in the Outer Mitochondrial Membrane01:12

Porin Insertion in the Outer Mitochondrial Membrane

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...
4.1K
Mitochondria01:37

Mitochondria

Mitochondria are eukaryotic cellular organelles that are known to produce energy through a process called oxidative phosphorylation. Besides their primary function, mitochondria are involved in various cellular processes, including cell growth, differentiation, signaling, metabolism, and senescence. Age-related changes cause a decline in mitochondrial quality and integrity due to increased mitochondrial mutations and oxidative damage. Thus, aging can severely impact mitochondrial functions,...
18.5K
Protein Transport into the Inner Mitochondrial Membrane01:34

Protein Transport into the Inner Mitochondrial Membrane

Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
4.6K