• Início
  • Resultados da busca
  • Two distinct actin filament populations have effects on mitochondria, with differences in stimuli and assembly factors.

Two distinct actin filament populations have effects on mitochondria, with differences in stimuli and assembly factors.

Journal of cell science (2019-08-16)
Tak Shun Fung, Wei-Ke Ji, Henry N Higgs, Rajarshi Chakrabarti
RESUMO

Recent studies show that mitochondria and actin filaments work together in two contexts: (1) increased cytoplasmic calcium induces cytoplasmic actin polymerization that stimulates mitochondrial fission and (2) mitochondrial depolarization causes actin assembly around mitochondria, with roles in mitophagy. It is unclear whether these two processes utilize similar actin assembly mechanisms. Here, we show that these are distinct actin assembly mechanisms in the acute phase after treatment (<10 min). Calcium-induced actin assembly is INF2 dependent and Arp2/3 complex independent, whereas depolarization-induced actin assembly is Arp2/3 complex dependent and INF2 independent. The two types of actin polymerization are morphologically distinct, with calcium-induced filaments throughout the cytosol and depolarization-induced filaments as 'clouds' around depolarized mitochondria. We have previously shown that calcium-induced actin stimulates increases in both mitochondrial calcium and recruitment of the dynamin GTPase Drp1 (also known as DNM1L). In contrast, depolarization-induced actin is temporally associated with extensive mitochondrial dynamics that do not result in mitochondrial fission, but in circularization of the inner mitochondrial membrane (IMM). These dynamics are dependent on the protease OMA1 and independent of Drp1. Actin cloud inhibition causes increased IMM circularization, suggesting that actin clouds limit these dynamics.This article has an associated First Person interview with the first author of the paper.

MATERIAIS
Número do produto
Marca
Descrição do produto

Sigma-Aldrich
Ionomycin calcium salt from Streptomyces conglobatus, powder, ≥98% (HPLC)
Sigma-Aldrich
LookOut® Mycoplasma PCR Detection Kit, Optimized for use with JumpStart Taq DNA Polymerase, D9307.
Sigma-Aldrich
Monoclonal Anti-α-Tubulin antibody produced in mouse, clone DM1A, ascites fluid
Sigma-Aldrich
Carbonyl cyanide 3-chlorophenylhydrazone, ≥97% (TLC), powder
Sigma-Aldrich
Tetramethylrhodamine ethyl ester perchlorate, suitable for fluorescence, ≥90% (HPCE)