The Molecular Assembly State of Drp1 Controls its Association With the Mitochondrial Recruitment Receptors Mff and MIEF1/2

Abstract

Drp1 is a central player in mitochondrial fission and is recruited to mitochondria by Mff and MIEFs (MIEF1 and MIEF2), but little is known about how its assembly state affects Drp1 mitochondrial recruitment and fission. Here, we used in vivo chemical crosslinking to explore the self-assembly state of Drp1 and how it regulates the association of Drp1 with MIEFs and Mff. We show that in intact mammalian cells Drp1 exists as a mixture of multiple self-assembly forms ranging from the minimal, probably tetrameric, self-assembly subunit to several higher order oligomers. Precluding mitochondria-bound Drp1 in Mff/MIEF1/2-deficient cells does not affect the oligomerization state of Drp1, while conversely forced recruitment of Drp1 to mitochondria by MIEFs or Mff facilitates Drp1 oligomerization. Mff preferentially binds to higher order oligomers of Drp1, whereas MIEFs bind to a wider-range of Drp1 assembly subunits, including both lower and higher oligomeric states. Mff only recruits active forms of Drp1, while MIEFs are less selective and recruit both active and inactive Drp1 as well as oligomerization- or GTPase-deficient Drp1 mutants to mitochondria. Moreover, all the fission-incompetent Drp1 mutants tested (except the monomeric mutant K668E) affect Drp1-driven mitochondrial dynamics via incorporation of the mutants into the native oligomers to form function-deficient Drp1 assemblies. We here confirm that MIEFs also serve as a platform facilitating the binding of Drp1 to Mff and loss of MIEFs severely impairs the interaction between Drp1 and Mff. Collectively, our findings suggest that Mff and MIEFs respond differently to the molecular assembly state of Drp1 and that the extent of Drp1 oligomerization regulates mitochondrial dynamics.

AMPK Activation Alleviates Myocardial Ischemia-Reperfusion Injury by Regulating Drp1-Mediated Mitochondrial Dynamics

“…Drp1, located in the cytosol, is essential for mitochondrial fission ( Bradshaw et al, 2016 ). During mitochondrial fission, cytosolic Drp1 is recruited to mitochondria, binds to adaptors on mitochondrial outer membranes, and assembles into oligomers to constrict and sever mitochondrial membranes ( van der Bliek et al, 2013 ; Yu et al, 2021 ). The most characteristic mechanism of post-translational modification in Drp-1 involves phosphorylation at two key sites: Drp1 (Ser616) and Drp1 (Ser637) ( Chang and Blackstone, 2010 ).…”

Inhibitors of Mitochondrial Dynamics Mediated by Dynamin-Related Protein 1 in Pulmonary Arterial Hypertension

“…After that, Palmer et al found that MiD49/MiD51 had more Drp1 recruitment activity than Mff and Fis1, it could recruit both high and low oligomers of Drp1 (Palmer et al, 2011). Moreover, Yu et al (2021) confirmed that the different assembly state of Drp1 oligomerization in turn affect the aggregation of OMM ligands, and the balance of mitochondrial dynamics (Yu et al, 2021).…”

What Is the Role of Mitochondrial Fission in Neurologic Disease?

“…26 Adenosine monophosphate-activated protein kinase phosphorylates MFF to promote mitochondrial fission in the setting of energy deficiency. 27 MIEFs serve as adaptors linking DRP1 and MFF together in a trimeric DRP1-Mid (MIEF)-MFF complex 23 and function as a central hub that regulates both the fission and fusion machineries. 28 GDAP1 is an outer mitochondrial membrane-anchored protein that regulates mitochondrial fission by cooperating with DRP1 and Fis1.…”

“…(MFF), mitochondrial dynamics proteins of 49 and 51 KDa (Mid49/51, also known as mitochondrial elongation factors [MIEF] 1 and 2), mitochondrial protein 18 kDA (MTP18, also referred to as mitochondrial fission process 1 [MTFP1]), and ganglioside-induced differentiationassociated protein 1 (GDAP1). [18][19][20][21][22][23][24][25] The DRP1-MFF interaction is critical for physiologic mitochondrial fission. 26 Adenosine monophosphate-activated protein kinase phosphorylates MFF to promote mitochondrial fission in the setting of energy deficiency.…”