Direct Interaction of Mitochondrial Targeting Presequences with Purified Components of the TIM23 Protein Complex

Marom, Milit; Dayan, Danit; Demishtein-Zohary, Keren; Mokranjac, Dejana; Neupert, Walter; Azem, Abdussalam

doi:10.1074/jbc.m111.261040

Cited by 52 publications

(56 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After import, samples were analyzed by SDS-PAGE or blue-native PAGE (BN-PAGE), and 35 S-labeled proteins were detected by digital autoradiography and quantified using ImageQuant TL software (GE Healthcare).…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…For synthesis of 35 S-labeled precursor proteins, the respective open reading frames were cloned downstream of the SP6 promoter in pGEM4Z (Promega) or pCR-Blunt2-TOPO (Invitrogen). Plasmids were used to synthesize 35 S-labeled precursor proteins by coupled in vitro transcriptiontranslation (TNT quick coupled transcription-translation system; Promega). Alternatively, the open reading frames were amplified from plasmid DNA by PCR, transcribed and purified (mMessage mMachine SP6 system and MEGAclear kit; Ambion), and subsequently used for in vitro translation (Flexi rabbit reticulocyte lysate system; Promega).…”

Section: Methodsmentioning

confidence: 99%

“…In contrast to metabolite carriers and channels of the inner mitochondrial membrane, a group of multispanning membrane proteins, such as the ABC transporters and the insertase OxaI, contain N-terminal presequences (2,16,20). The insertion of these proteins into the lipid phase requires the presequence translocase (TIM23 complex), which initially recognizes the precursor through an interaction between the presequence and the receptor Tim50 (35,56). Recognition of the presequence is thought to activate the translocase and thus to initiate membrane translocation (66).…”

mentioning

confidence: 99%

See 3 more Smart Citations

The Channel-Forming Sym1 Protein Is Transported by the TIM23 Complex in a Presequence-Independent Manner

Reinhold

Krüger

Meinecke

et al. 2012

Molecular and Cellular Biology

View full text Add to dashboard Cite

fThe majority of multispanning inner mitochondrial membrane proteins utilize internal targeting signals, which direct them to the carrier translocase (TIM22 complex), for their import. MPV17 and its Saccharomyces cerevisiae orthologue Sym1 are multispanning inner membrane proteins of unknown function with an amino-terminal presequence that suggests they may be targeted to the mitochondria. Mutations affecting MPV17 are associated with mitochondrial DNA depletion syndrome (MDDS). Reconstitution of purified Sym1 into planar lipid bilayers and electrophysiological measurements have demonstrated that Sym1 forms a membrane pore. To address the biogenesis of Sym1, which oligomerizes in the inner mitochondrial membrane, we studied its import and assembly pathway. Sym1 forms a transport intermediate at the translocase of the outer membrane (TOM) complex. Surprisingly, Sym1 was not transported into mitochondria by an amino-terminal signal, and in contrast to what has been observed in carrier proteins, Sym1 transport and assembly into the inner membrane were independent of small translocase of mitochondrial inner membrane (TIM) and TIM22 complexes. Instead, Sym1 required the presequence of translocase for its biogenesis. Our analyses have revealed a novel transport mechanism for a polytopic membrane protein in which internal signals direct the precursor into the inner membrane via the TIM23 complex, indicating a presequence-independent function of this translocase.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

The Channel-Forming Sym1 Protein Is Transported by the TIM23 Complex in a Presequence-Independent Manner

Reinhold

Krüger

Meinecke

et al. 2012

Molecular and Cellular Biology

View full text Add to dashboard Cite

show abstract

“…2). The first subunit of the TIM23 complex encountered by an incoming precursor protein on the trans-side of the TOM complex is Tim50 (26)(27)(28)(29). Tim50 passes the presequence to the channel forming unit of TIM23 formed by the Tim23 and Tim17 proteins.…”

Section: Figmentioning

confidence: 99%

Mitochondrial protein homeostasis

2013

View full text Add to dashboard Cite

Mitochondria use 800-1,500 proteins to perform their biological functions in the eukaryotic cells. Distinct transport and sorting mechanisms are responsible for the delivery of proteins to the correct location within mitochondria. Mitochondrial proteins undergo processing events and form functional assemblies.Finally, non-functional proteins are cleared to maintain healthy mitochondria. We provide an overview of the processes collectively contributing to the maintenance of mitochondrial protein homeostasis, which is critical for cell physiology and survival.

show abstract

Role of membrane contact sites in protein import into mitochondria

et al. 2015

View full text Add to dashboard Cite

Mitochondria import more than 1,000 different proteins from the cytosol. The proteins are synthesized as precursors on cytosolic ribosomes and are translocated by protein transport machineries of the mitochondrial membranes. Five main pathways for protein import into mitochondria have been identified. Most pathways use the translocase of the outer mitochondrial membrane (TOM) as the entry gate into mitochondria. Depending on specific signals contained in the precursors, the proteins are subsequently transferred to different intramitochondrial translocases. In this article, we discuss the connection between protein import and mitochondrial membrane architecture. Mitochondria possess two membranes. It is a longstanding question how contact sites between outer and inner membranes are formed and which role the contact sites play in the translocation of precursor proteins. A major translocation contact site is formed between the TOM complex and the presequence translocase of the inner membrane (TIM23 complex), promoting transfer of presequence-carrying preproteins to the mitochondrial inner membrane and matrix. Recent findings led to the identification of contact sites that involve the mitochondrial contact site and cristae organizing system (MICOS) of the inner membrane. MICOS plays a dual role. It is crucial for maintaining the inner membrane cristae architecture and forms contacts sites to the outer membrane that promote translocation of precursor proteins into the intermembrane space and outer membrane of mitochondria. The view is emerging that the mitochondrial protein translocases do not function as independent units, but are embedded in a network of interactions with machineries that control mitochondrial activity and architecture.

show abstract

Direct Interaction of Mitochondrial Targeting Presequences with Purified Components of the TIM23 Protein Complex

Cited by 52 publications

References 37 publications

The Channel-Forming Sym1 Protein Is Transported by the TIM23 Complex in a Presequence-Independent Manner

The Channel-Forming Sym1 Protein Is Transported by the TIM23 Complex in a Presequence-Independent Manner

Mitochondrial protein homeostasis

Role of membrane contact sites in protein import into mitochondria

Contact Info

Product

Resources

About