Move it on over: getting proteins across biological membranes

Eichler, Jerry; Irihimovitch, Vered

doi:10.1002/bies.10382

Cited by 6 publications

(4 citation statements)

References 43 publications

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“…Diverse machineries involved in translocating proteins across organellar membranes are required to maintain the compartmentalization of biological processes within eukaryotic cells (Kunau et al, 2001;Wickner and Schekman, 2005). Many components of membrane receptors recognize specific targeting sequences in proteins destined for translocation (Eichler and Irihimovitch, 2003). However, they differ in their requirements for cargo folding/unfolding during the translocation process to retain the functional integrity of the cargo.…”

Section: Introductionmentioning

confidence: 99%

Recognition of a Functional Peroxisome Type 1 Target by the Dynamic Import Receptor Pex5p

et al. 2006

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Peroxisomes require the translocation of folded and functional target proteins of various sizes across the peroxisomal membrane. We have investigated the structure and function of the principal import receptor Pex5p, which recognizes targets bearing a C-terminal peroxisomal targeting signal type 1. Crystal structures of the receptor in the presence and absence of a peroxisomal target, sterol carrier protein 2, reveal major structural changes from an open, snail-like conformation into a closed, circular conformation. These changes are caused by a long loop C terminal to the 7-fold tetratricopeptide repeat segments. Mutations in residues of this loop lead to defects in peroxisomal import in human fibroblasts. The structure of the receptor/cargo complex demonstrates that the primary receptor-binding site of the cargo is structurally and topologically autonomous, enabling the cargo to retain its native structure and function.

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Section: Introductionmentioning

confidence: 99%

Recognition of a Functional Peroxisome Type 1 Target by the Dynamic Import Receptor Pex5p

et al. 2006

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“…Protein translocators have been studied in many systems, particularly eukaryotic organellar import machinery and the bacterial SecYEG export complex1819. Characterization of these systems has relied on in vitro biochemical assays and creation of transport mutants that prevent translocation, for example fusion to a dihydrofolate reductase (DHFR) tag.…”

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confidence: 99%

Spatial association with PTEX complexes defines regions for effector export into Plasmodium falciparum-infected erythrocytes

Riglar

Rogers

Hanssen³

et al. 2013

Nat Commun

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Export of proteins into the infected erythrocyte is critical for malaria parasite survival. The majority of effector proteins are thought to export via a proteinaceous translocon, resident in the parasitophorous vacuole membrane surrounding the parasite. Identification of the Plasmodium translocon of exported proteins and its biochemical association with exported proteins suggests it performs this role. Direct evidence for this, however, is lacking. Here using viable purified Plasmodium falciparum merozoites and three-dimensional structured illumination microscopy, we investigate remodelling events immediately following parasite invasion. We show that multiple complexes of the Plasmodium translocon of exported proteins localize together in foci that dynamically change in clustering behaviour. Furthermore, we provide conclusive evidence of spatial association between exported proteins and exported protein 2, a core component of the Plasmodium translocon of exported proteins, during native conditions and upon generation of translocation intermediates. These data provide the most direct cellular evidence to date that protein export occurs at regions of the parasitophorous vacuole membrane housing the Plasmodium translocon of exported proteins complex.

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“…Protein transport across, or integration into, biological membranes is a vital cellular process (1)(2)(3). Components of the Sec translocon, the membrane pore through which presecretory proteins (or membrane proteins) achieve membrane translocation (or integration), are the most conserved transport constituents throughout the three kingdoms of life (4).…”

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confidence: 99%

Demonstration of a Specific Escherichia coli SecY−Signal Peptide Interaction

et al. 2004

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Protein translocation in Escherichia coli is initiated by the interaction of a preprotein with the membrane translocase composed of a motor protein, SecA ATPase, and a membrane-embedded channel, the SecYEG complex. The extent to which the signal peptide region of the preprotein plays a role in SecYEG interactions is unclear, in part because studies in this area typically employ the entire preprotein. Using a synthetic signal peptide harboring a photoaffinity label in its hydrophobic core, we examined this interaction with SecYEG in a detergent micellar environment. The signal peptide was found to specifically bind SecY in a saturable manner and at levels comparable to those that stimulate SecA ATPase activity. Chemical and proteolytic cleavage of cross-linked SecY and analysis of the signal peptide adducts indicate that the binding was primarily to regions of the protein containing transmembrane domains seven and two. The signal peptide-SecY interaction was affected by the presence of SecA and nucleotides in a manner consistent with the transfer of signal peptide to SecY upon nucleotide hydrolysis at SecA. † This research was supported in part by National Institutes of Health Grant GM37639 (to D.A.K. Protein transport across, or integration into, biological membranes is a vital cellular process (1-3). Components of the Sec translocon, the membrane pore through which presecretory proteins (or membrane proteins) achieve membrane translocation (or integration), are the most conserved transport constituents throughout the three kingdoms of life (4).In Escherichia coli, the essential components of the translocase (5) include the membraneassociated form of SecA (6, 7) and the polytopic membrane proteins SecY, SecE (homologues of the mammalian Sec61α, Sec61γ, and the yeast ER 1 Sec61p, Sss1p, respectively), and SecG (8, 9); the latter three proteins form a stable trimeric SecYEG complex (10). SecA is an ATPase that powers the membrane translocation of hydrophilic polypeptides by coupling ATP hydrolysis with protein movement via concomitant SecA membrane insertion and deinsertion cycles (11,12). SecY protein has 10 transmembrane (TM1-TM10), six cytosolic (C1-C6), and five periplasmic (P1-P5) domains (13), and it forms the core of the passageway for the translocating polypeptide chain (14 (35,36). Suppressor analysis of prlA mutations using dysfunctional LamB signal peptides revealed that the suppressor mutations clustered in distinct regions, and TM7 of SecY was proposed to function in signal sequence recognition (37). Yet no investigation has focused on the direct interaction between a signal peptide and the E. coli translocon. Consequently, it remains unclear whether the nascent polypeptide chain is merely translocating in close proximity to SecY, SecY performs simply a proofreading function (37), or SecY is more intimately involved in the specific recognition of the signal peptide. Wang et al. Page 2Biochemistry. Author manuscript; available in PMC 2011 April 29. NIH-PA Author ManuscriptNIH-PA Author Manuscr...

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Move it on over: getting proteins across biological membranes

Cited by 6 publications

References 43 publications

Recognition of a Functional Peroxisome Type 1 Target by the Dynamic Import Receptor Pex5p

Recognition of a Functional Peroxisome Type 1 Target by the Dynamic Import Receptor Pex5p

Spatial association with PTEX complexes defines regions for effector export into Plasmodium falciparum-infected erythrocytes

Demonstration of a Specific Escherichia coli SecY−Signal Peptide Interaction

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