Related Experiment Video

Updated: May 15, 2026

Using Scaffold Liposomes to Reconstitute Lipid-proximal Protein-protein Interactions In Vitro
08:53

Using Scaffold Liposomes to Reconstitute Lipid-proximal Protein-protein Interactions In Vitro

Published on: January 11, 2017

Fis1, Mff, MiD49, and MiD51 mediate Drp1 recruitment in mitochondrial fission

Oliver C Losón1, Zhiyin Song, Hsiuchen Chen

  • 1Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.

Molecular Biology of the Cell
|January 4, 2013
PubMed

Insights

Mitochondrial fission relies on multiple proteins. Fis1 and Mff are crucial for recruiting Drp1, while MiD49 or MiD51 can independently mediate fission, revealing redundant pathways in mitochondrial dynamics.

Area of Science:

  • Cell Biology
  • Mitochondrial Dynamics
  • Protein Function

Background:

  • Mitochondrial outer membrane proteins like Fis1, Mff, MiD49, and MiD51 are implicated in recruiting Drp1 for mitochondrial fission.
  • Conflicting data exists regarding the roles of Fis1, Mff, MiD49, and MiD51 in mitochondrial fission, with some studies questioning Fis1's role and the function of MiD49/MiD51 due to overexpression effects.

Purpose of the Study:

  • To clarify the roles of Fis1 and Mff in mitochondrial fission.
  • To investigate whether MiD49 and MiD51 can mediate fission independently.
  • To determine if multiple receptors can recruit Drp1 for mitochondrial fission.

Main Methods:

  • Utilized Fis1-null, Mff-null, and Fis1/Mff-null cells to assess protein function.
  • Employed immunofluorescence analysis to examine Drp1 localization and puncta formation on mitochondria.
  • Investigated the recruitment of Drp1 and subsequent mitochondrial fission mediated by MiD49 and MiD51 in the absence of Fis1 and Mff.

Main Results:

  • Demonstrated that both Fis1 and Mff play significant roles in mitochondrial fission.
  • Found that Fis1 and Mff influence the number and size of Drp1 puncta on mitochondria.
  • Showed that MiD49 or MiD51 can independently recruit Drp1 and induce mitochondrial fission, even when Fis1 and Mff are absent.

Conclusions:

  • Confirms that Fis1 and Mff are important mediators of mitochondrial fission.
  • Establishes that MiD49 and MiD51 possess independent fission-mediating capabilities.
  • Highlights the existence of multiple, potentially redundant, Drp1 receptor systems for regulating mitochondrial fission.

More Related Videos

Studying Mitochondrial Structure and Function in Drosophila Ovaries09:53

Studying Mitochondrial Structure and Function in Drosophila Ovaries

Published on: January 4, 2017

Assessment of Mitochondrial Fission/Fusion Dynamics in Kidney Proximal Tubular Cells06:14

Assessment of Mitochondrial Fission/Fusion Dynamics in Kidney Proximal Tubular Cells

Published on: November 14, 2025

Related Concept Videos

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,...
Energy to Drive Translocation01:37

Energy to Drive Translocation

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...
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...
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...
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...
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 precursors...