1
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Hildebrandt ER, Hussain SA, Sieburg MA, Ravishankar R, Asad N, Gore S, Ito T, Hougland JL, Dore TM, Schmidt WK. Targeted genetic and small molecule disruption of N-Ras CaaX cleavage alters its localization and oncogenic potential. Bioorg Chem 2024; 147:107316. [PMID: 38583246 PMCID: PMC11098683 DOI: 10.1016/j.bioorg.2024.107316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/16/2024] [Accepted: 03/26/2024] [Indexed: 04/09/2024]
Abstract
Ras GTPases and other CaaX proteins undergo multiple post-translational modifications at their carboxyl-terminus. These events initiate with prenylation of a cysteine and are followed by endoproteolytic removal of the 'aaX' tripeptide and carboxylmethylation. Some CaaX proteins are only subject to prenylation, however, due to the presence of an uncleavable sequence. In this study, uncleavable sequences were used to stage Ras isoforms in a farnesylated and uncleaved state to address the impact of CaaX proteolysis on protein localization and function. This targeted strategy is more specific than those that chemically inhibit the Rce1 CaaX protease or delete the RCE1 gene because global abrogation of CaaX proteolysis impacts the entire CaaX protein proteome and effects cannot be attributed to any specific CaaX protein of the many concurrently affected. With this targeted strategy, clear mislocalization and reduced activity of farnesylated and uncleaved Ras isoforms was observed. In addition, new peptidomimetics based on cleavable Ras CaaX sequences and the uncleavable CAHQ sequence were synthesized and tested as Rce1 inhibitors using in vitro and cell-based assays. Consistently, these non-hydrolyzable peptidomimetic Rce1 inhibitors recapitulate Ras mislocalization effects when modeled on cleavable but not uncleavable CaaX sequences. These findings indicate that a prenylated and uncleavable CaaX sequence, which can be easily applied to a wide range of mammalian CaaX proteins, can be used to probe the specific impact of CaaX proteolysis on CaaX protein properties under conditions of an otherwise normally processed CaaX protein proteome.
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Affiliation(s)
- Emily R Hildebrandt
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - Shaneela A Hussain
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | | | - Rajani Ravishankar
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - Nadeem Asad
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | - Sangram Gore
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | - Takahiro Ito
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA; Department of Biology, Syracuse University, Syracuse, NY, USA; BioInspired Syracuse, Syracuse University, Syracuse, NY, USA
| | - Timothy M Dore
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE; Department of Chemistry, University of Georgia, Athens, GA, USA
| | - Walter K Schmidt
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA.
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2
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Hildebrandt ER, Sarkar A, Ravishankar R, Kim JH, Schmidt WK. Evaluating protein prenylation of human and viral CaaX sequences using a humanized yeast system. Dis Model Mech 2024; 17:dmm050516. [PMID: 38818856 PMCID: PMC11152559 DOI: 10.1242/dmm.050516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 04/23/2024] [Indexed: 06/01/2024] Open
Abstract
Prenylated proteins are prevalent in eukaryotic biology (∼1-2% of proteins) and are associated with human disease, including cancer, premature aging and infections. Prenylated proteins with a C-terminal CaaX sequence are targeted by CaaX-type prenyltransferases and proteases. To aid investigations of these enzymes and their targets, we developed Saccharomyces cerevisiae strains that express these human enzymes instead of their yeast counterparts. These strains were developed in part to explore human prenyltransferase specificity because of findings that yeast FTase has expanded specificity for sequences deviating from the CaaX consensus (i.e. atypical sequence and length). The humanized yeast strains displayed robust prenyltransferase activity against CaaX sequences derived from human and pathogen proteins containing typical and atypical CaaX sequences. The system also recapitulated prenylation of heterologously expressed human proteins (i.e. HRas and DNAJA2). These results reveal that substrate specificity is conserved for yeast and human farnesyltransferases but is less conserved for type I geranylgeranyltransferases. These yeast systems can be easily adapted for investigating the prenylomes of other organisms and are valuable new tools for helping define the human prenylome, which includes physiologically important proteins for which the CaaX modification status is unknown.
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Affiliation(s)
- Emily R. Hildebrandt
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Anushka Sarkar
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Rajani Ravishankar
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - June H. Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Walter K. Schmidt
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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3
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Runnebohm AM, Indovina CJ, Turk SM, Bailey CG, Orchard CJ, Wade L, Overton DL, Snow BJ, Rubenstein EM. Methionine Restriction Impairs Degradation of a Protein that Aberrantly Engages the Endoplasmic Reticulum Translocon. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.001021. [PMID: 38021175 PMCID: PMC10667923 DOI: 10.17912/micropub.biology.001021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/01/2023] [Accepted: 11/07/2023] [Indexed: 12/01/2023]
Abstract
Proteins that persistently engage endoplasmic reticulum (ER) translocons are degraded by multiple translocon quality control (TQC) mechanisms. In Saccharomyces cerevisiae , the model translocon-associated protein Deg1 -Sec62 is subject to ER-associated degradation (ERAD) by the Hrd1 ubiquitin ligase and, to a lesser extent, proteolysis mediated by the Ste24 protease. In a recent screen, we identified nine methionine-biosynthetic genes as candidate TQC regulators. Here, we found methionine restriction impairs Hrd1-independent Deg1 -Sec62 degradation. Beyond revealing methionine as a novel regulator of TQC, our results urge caution when working with laboratory yeast strains with auxotrophic mutations, often presumed not to influence cellular processes under investigation.
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Affiliation(s)
- Avery M. Runnebohm
- Department of Biology, Ball State University, Muncie, Indiana, United States
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | | | - Samantha M. Turk
- Department of Biology, Ball State University, Muncie, Indiana, United States
- St. Jude Graduate School of Biomedical Science, Memphis, Tennessee, United States
| | - Connor G. Bailey
- Department of Biology, Ball State University, Muncie, Indiana, United States
- AllSource PPS, United States
| | - Cade J. Orchard
- Department of Biology, Ball State University, Muncie, Indiana, United States
- Department of Geology, University of Georgia, Athens, Georgia, United States
| | - Lauren Wade
- Department of Biology, Ball State University, Muncie, Indiana, United States
- Flow Cytometry Department, LabCorp, United States
| | - Danielle L. Overton
- Department of Biology, Ball State University, Muncie, Indiana, United States
- Department of Biology, Indiana University – Purdue University Indianapolis, Indianapolis, Indiana, United States
| | - Brian J. Snow
- Department of Biology, Ball State University, Muncie, Indiana, United States
- Department of Pathology and Laboratory Medicine, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Eric M. Rubenstein
- Department of Biology, Ball State University, Muncie, Indiana, United States
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4
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Hildebrandt ER, Sarkar A, Ravishankar R, Kim JH, Schmidt WK. A Humanized Yeast System for Evaluating the Protein Prenylation of a Wide Range of Human and Viral CaaX Sequences. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558494. [PMID: 37786692 PMCID: PMC10541624 DOI: 10.1101/2023.09.19.558494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
The C-terminal CaaX sequence (cysteine-aliphatic-aliphatic-any of several amino acids) is subject to isoprenylation on the conserved cysteine and is estimated to occur in 1-2% of proteins within yeast and human proteomes. Recently, non-canonical CaaX sequences in addition to shorter and longer length CaX and CaaaX sequences have been identified that can be prenylated. Much of the characterization of prenyltransferases has relied on the yeast system because of its genetic tractability and availability of reporter proteins, such as the a-factor mating pheromone, Ras GTPase, and Ydj1 Hsp40 chaperone. To compare the properties of yeast and human prenyltransferases, including the recently expanded target specificity of yeast farnesyltransferase, we have developed yeast strains that express human farnesyltransferase or geranylgeranyltransferase-I in lieu of their yeast counterparts. The humanized yeast strains display robust prenyltransferase activity that functionally replaces yeast prenyltransferase activity in a wide array of tests, including the prenylation of a wide variety of canonical and non-canonical human CaaX sequences, virus encoded CaaX sequences, non-canonical length sequences, and heterologously expressed human proteins HRas and DNAJA2. These results reveal highly overlapping substrate specificity for yeast and human farnesyltransferase, and mostly overlapping substrate specificity for GGTase-I. This yeast system is a valuable tool for further defining the prenylome of humans and other organisms, identifying proteins for which prenylation status has not yet been determined.
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Affiliation(s)
| | - Anushka Sarkar
- Department of Biochemistry and Molecular Biology, University of Georgia
| | | | - June H. Kim
- Department of Biochemistry and Molecular Biology, University of Georgia
| | - Walter K. Schmidt
- Department of Biochemistry and Molecular Biology, University of Georgia
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5
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Primmer SR, Liao CY, Kummert OMP, Kennedy BK. Lamin A to Z in normal aging. Aging (Albany NY) 2022; 14:8150-8166. [PMID: 36260869 DOI: 10.18632/aging.204342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/31/2022] [Indexed: 11/25/2022]
Abstract
Almost since the discovery that mutations in the LMNA gene, encoding the nuclear structure components lamin A and C, lead to Hutchinson-Gilford progeria syndrome, people have speculated that lamins may have a role in normal aging. The most common HPGS mutation creates a splice variant of lamin A, progerin, which promotes accelerated aging pathology. While some evidence exists that progerin accumulates with normal aging, an increasing body of work indicates that prelamin A, a precursor of lamin A prior to C-terminal proteolytic processing, accumulates with age and may be a driver of normal aging. Prelamin A shares properties with progerin and is also linked to a rare progeroid disease, restrictive dermopathy. Here, we describe mechanisms underlying changes in prelamin A with aging and lay out the case that this unprocessed protein impacts normative aging. This is important since intervention strategies can be developed to modify this pathway as a means to extend healthspan and lifespan.
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Affiliation(s)
| | - Chen-Yu Liao
- The Buck Institute for Research on Aging, Novato, CA 94945, USA
| | | | - Brian K Kennedy
- Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Centre for Healthy Longevity, National University Health System, Singapore.,Departments of Biochemistry and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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6
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Berger BM, Yeung W, Goyal A, Zhou Z, Hildebrandt ER, Kannan N, Schmidt WK. Functional classification and validation of yeast prenylation motifs using machine learning and genetic reporters. PLoS One 2022; 17:e0270128. [PMID: 35749383 PMCID: PMC9231725 DOI: 10.1371/journal.pone.0270128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 06/05/2022] [Indexed: 11/19/2022] Open
Abstract
Protein prenylation by farnesyltransferase (FTase) is often described as the targeting of a cysteine-containing motif (CaaX) that is enriched for aliphatic amino acids at the a1 and a2 positions, while quite flexible at the X position. Prenylation prediction methods often rely on these features despite emerging evidence that FTase has broader target specificity than previously considered. Using a machine learning approach and training sets based on canonical (prenylated, proteolyzed, and carboxymethylated) and recently identified shunted motifs (prenylation only), this study aims to improve prenylation predictions with the goal of determining the full scope of prenylation potential among the 8000 possible Cxxx sequence combinations. Further, this study aims to subdivide the prenylated sequences as either shunted (i.e., uncleaved) or cleaved (i.e., canonical). Predictions were determined for Saccharomyces cerevisiae FTase and compared to results derived using currently available prenylation prediction methods. In silico predictions were further evaluated using in vivo methods coupled to two yeast reporters, the yeast mating pheromone a-factor and Hsp40 Ydj1p, that represent proteins with canonical and shunted CaaX motifs, respectively. Our machine learning-based approach expands the repertoire of predicted FTase targets and provides a framework for functional classification.
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Affiliation(s)
- Brittany M. Berger
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Wayland Yeung
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, United States of America
| | - Arnav Goyal
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Zhongliang Zhou
- Department of Computer Science, University of Georgia, Athens, Georgia, United States of America
| | - Emily R. Hildebrandt
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Natarajan Kannan
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, United States of America
| | - Walter K. Schmidt
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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7
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Wood KM, Spear ED, Mossberg OW, Odinammadu KO, Xu W, Michaelis S. Defining substrate requirements for cleavage of farnesylated prelamin A by the integral membrane zinc metalloprotease ZMPSTE24. PLoS One 2020; 15:e0239269. [PMID: 33315887 PMCID: PMC7735620 DOI: 10.1371/journal.pone.0239269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023] Open
Abstract
The integral membrane zinc metalloprotease ZMPSTE24 plays a key role in the proteolytic processing of farnesylated prelamin A, the precursor of the nuclear scaffold protein lamin A. Failure of this processing step results in the accumulation of permanently farnesylated forms of prelamin A which cause the premature aging disease Hutchinson-Gilford Progeria Syndrome (HGPS), as well as related progeroid disorders, and may also play a role in physiological aging. ZMPSTE24 is an intriguing and unusual protease because its active site is located inside of a closed intramembrane chamber formed by seven transmembrane spans with side portals in the chamber permitting substrate entry. The specific features of prelamin A that make it the sole known substrate for ZMPSTE24 in mammalian cells are not well-defined. At the outset of this work it was known that farnesylation is essential for prelamin A cleavage in vivo and that the C-terminal region of prelamin A (41 amino acids) is sufficient for recognition and processing. Here we investigated additional features of prelamin A that are required for cleavage by ZMPSTE24 using a well-established humanized yeast system. We analyzed the 14-residue C-terminal region of prelamin A that lies between the ZMPSTE24 cleavage site and the farnesylated cysteine, as well 23-residue region N-terminal to the cleavage site, by generating a series of alanine substitutions, alanine additions, and deletions in prelamin A. Surprisingly, we found that there is considerable flexibility in specific requirements for the length and composition of these regions. We discuss how this flexibility can be reconciled with ZMPSTE24's selectivity for prelamin A.
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Affiliation(s)
- Kaitlin M. Wood
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Eric D. Spear
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Otto W. Mossberg
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Kamsi O. Odinammadu
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Wenxin Xu
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Susan Michaelis
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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8
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Babatz TD, Spear ED, Xu W, Sun OL, Nie L, Carpenter EP, Michaelis S. Site specificity determinants for prelamin A cleavage by the zinc metalloprotease ZMPSTE24. J Biol Chem 2020; 296:100165. [PMID: 33293369 PMCID: PMC7948416 DOI: 10.1074/jbc.ra120.015792] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 01/11/2023] Open
Abstract
The integral membrane zinc metalloprotease ZMPSTE24 is important for human health and longevity. ZMPSTE24 performs a key proteolytic step in maturation of prelamin A, the farnesylated precursor of the nuclear scaffold protein lamin A. Mutations in the genes encoding either prelamin A or ZMPSTE24 that prevent cleavage cause the premature aging disease Hutchinson–Gilford progeria syndrome (HGPS) and related progeroid disorders. ZMPSTE24 has a novel structure, with seven transmembrane spans that form a large water-filled membrane chamber whose catalytic site faces the chamber interior. Prelamin A is the only known mammalian substrate for ZMPSTE24; however, the basis of this specificity remains unclear. To define the sequence requirements for ZMPSTE24 cleavage, we mutagenized the eight residues flanking the prelamin A scissile bond (TRSY↓LLGN) to all other 19 amino acids, creating a library of 152 variants. We also replaced these eight residues with sequences derived from putative ZMPSTE24 cleavage sites from amphibian, bird, and fish prelamin A. Cleavage of prelamin A variants was assessed using an in vivo yeast assay that provides a sensitive measure of ZMPSTE24 processing efficiency. We found that residues on the C-terminal side of the cleavage site are most sensitive to changes. Consistent with other zinc metalloproteases, including thermolysin, ZMPSTE24 preferred hydrophobic residues at the P1’ position (Leu647), but in addition, showed a similar, albeit muted, pattern at P2’. Our findings begin to define a consensus sequence for ZMPSTE24 that helps to clarify how this physiologically important protease functions and may ultimately lead to identifying additional substrates.
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Affiliation(s)
- Timothy D Babatz
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore Maryland, USA
| | - Eric D Spear
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore Maryland, USA
| | - Wenxin Xu
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore Maryland, USA
| | - Olivia L Sun
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore Maryland, USA
| | - Laiyin Nie
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Elisabeth P Carpenter
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Oxford, UK
| | - Susan Michaelis
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore Maryland, USA.
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9
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Goblirsch BR, Wiener MC. Ste24: An Integral Membrane Protein Zinc Metalloprotease with Provocative Structure and Emergent Biology. J Mol Biol 2020; 432:5079-5090. [PMID: 32199981 PMCID: PMC7172729 DOI: 10.1016/j.jmb.2020.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 03/06/2020] [Accepted: 03/12/2020] [Indexed: 01/30/2023]
Abstract
Ste24, an integral membrane protein zinc metalloprotease, is found in every kingdom of eukaryotes. It was discovered approximately 20 years ago by yeast genetic screens identifying it as a factor responsible for processing the yeast mating a-factor pheromone. In animals, Ste24 processes prelamin A, a component of the nuclear lamina; mutations in the human ortholog of Ste24 diminish its activity, giving rise to genetic diseases of accelerated aging (progerias). Additionally, lipodystrophy, acquired from the standard highly active antiretroviral therapy used to treat AIDS patients, likely results from off-target interactions of HIV (aspartyl) protease inhibitor drugs with Ste24. Ste24 possesses a novel “α-barrel” structure, consisting of a ring of seven transmembrane α-helices enclosing a large (> 12,000 Å3) interior volume that contains the active-site and substrate-binding region; this “membrane-interior reaction chamber” is unprecedented in integral membrane protein structures. Additionally, the surface of the membrane-interior reaction chamber possesses a strikingly large negative electrostatic surface potential, adding additional “functional mystery.” Recent publications implicate Ste24 as a key factor in several endoplasmic reticulum processes, including the unfolded protein response, a cellular stress response of the endoplasmic reticulum, and removal of misfolded proteins from the translocon. Ste24, with its provocative structure, enigmatic mechanism, and recently emergent new biological roles including “translocon unclogger” and (non-enyzmatic) broad-spectrum viral restriction factor, presents far differently than before 2016, when it was viewed as a “CAAX protease” responsible for cleavage of prenylated (farnesylated or geranylgeranylated) substrates. The emphasis of this review is on Ste24 of the “Post-CAAX-Protease Era.” Ste24 is a eukaryotic integral membrane protein of novel structure. Ste24 is a gluzincin ZMP whose structure/function relationships are poorly explored. ZMP core, ZMP accessory, and “ɑ-barrel modules form the Ste24 tripartite architecture. Emergent biology of Ste24 includes roles as a translocon unclogger and a viral restriction factor.
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Affiliation(s)
- Brandon R Goblirsch
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Michael C Wiener
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.
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10
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Goblirsch BR, Pryor EE, Wiener MC. The tripartite architecture of the eukaryotic integral membrane protein zinc metalloprotease Ste24. Proteins 2019; 88:604-615. [PMID: 31644822 PMCID: PMC7168092 DOI: 10.1002/prot.25841] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/04/2019] [Accepted: 10/15/2019] [Indexed: 12/22/2022]
Abstract
Ste24 enzymes, a family of eukaryotic integral membrane proteins, are zinc metalloproteases (ZMPs) originally characterized as “CAAX proteases” targeting prenylated substrates, including a‐factor mating pheromone in yeast and prelamin A in humans. Recently, Ste24 was shown to also cleave nonprenylated substrates. Reduced activity of the human ortholog, HsSte24, is linked to multiple disease states (laminopathies), including progerias and lipid disorders. Ste24 possesses a unique “α‐barrel” structure consisting of seven transmembrane (TM) α‐helices encircling a large intramembranous cavity (~14 000 Å3). The catalytic zinc, coordinated via a HExxH…E/H motif characteristic of gluzincin ZMPs, is positioned at one of the cavity's bases. The interrelationship between Ste24 as a gluzincin, a long‐studied class of soluble ZMPs, and as a novel cavity‐containing integral membrane protein protease has been minimally explored to date. Informed by homology to well‐characterized soluble, gluzincin ZMPs, we develop a model of Ste24 that provides a conceptual framework for this enzyme family, suitable for development and interpretation of structure/function studies. The model consists of an interfacial, zinc‐containing “ZMP Core” module surrounded by a “ZMP Accessory” module, both capped by a TM helical “α‐barrel” module of as yet unknown function. Multiple sequence alignment of 58 Ste24 orthologs revealed 38 absolutely conserved residues, apportioned unequally among the ZMP Core (18), ZMP Accessory (13), and α‐barrel (7) modules. This Tripartite Architecture representation of Ste24 provides a unified image of this enzyme family.
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Affiliation(s)
- Brandon R Goblirsch
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Edward E Pryor
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Michael C Wiener
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
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11
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Hsu ET, Vervacke JS, Distefano MD, Hrycyna CA. A Quantitative FRET Assay for the Upstream Cleavage Activity of the Integral Membrane Proteases Human ZMPSTE24 and Yeast Ste24. Methods Mol Biol 2019; 2009:279-293. [PMID: 31152411 DOI: 10.1007/978-1-4939-9532-5_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The integral membrane protease ZMPSTE24 plays an important role in the lamin A maturation pathway. ZMPSTE24 is the only known enzyme to cleave the last 15 residues from the C-terminus of prelamin A, including a farnesylated and carboxyl methylated cysteine. Mutations in ZMPSTE24 lead to progeroid diseases with abnormal prelamin A accumulation in the nucleus. Ste24 is the yeast functional homolog of ZMPSTE24 and similarly cleaves the a-factor pheromone precursor during its posttranslational maturation. To complement established qualitative techniques used to detect the upstream enzymatic cleavage by ZMPSTE24 and Ste24, including gel-shift assays and mass spectrometry analyses, we developed an enzymatic in vitro FRET-based assay to quantitatively measure the upstream cleavage activities of these two enzymes. This assay uses either purified enzyme or enzyme in crude membrane preparations and a 33-amino acid a-factor analog peptide that is a substrate for both Ste24 and ZMPSTE24. This peptide contains a fluorophore (2-aminobenzoic acid-Abz) at its N-terminus and a quencher moiety (dinitrophenol-DNP) positioned four residues downstream from the cleavage site. Upon cleavage, a fluorescent signal is generated in real time at 420 nm that is proportional to cleavage of the peptide and these kinetic data are used to quantify activity. This assay should provide a useful tool for kinetic analysis and for studying the catalytic mechanism of both ZMPSTE24 and Ste24.
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Affiliation(s)
- Erh-Ting Hsu
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | | | - Mark D Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
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12
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Goblirsch BR, Arachea BT, Councell DJ, Wiener MC. Phosphoramidon inhibits the integral membrane protein zinc metalloprotease ZMPSTE24. Acta Crystallogr D Struct Biol 2018; 74:739-747. [PMID: 30082509 PMCID: PMC6079626 DOI: 10.1107/s2059798318003431] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 02/27/2018] [Indexed: 11/10/2022] Open
Abstract
The integral membrane protein zinc metalloprotease ZMPSTE24 possesses a completely novel structure, comprising seven long kinked transmembrane helices that encircle a voluminous 14 000 Å3 cavity within the membrane. Functionally conserved soluble zinc metalloprotease residues are contained within this cavity. As part of an effort to understand the structural and functional relationships between ZMPSTE24 and soluble zinc metalloproteases, the inhibition of ZMPSTE24 by phosphoramidon [N-(α-rhamnopyranosyl-oxyhydroxyphosphinyl)-Leu-Trp], a transition-state analog and competitive inhibitor of multiple soluble zinc metalloproteases, especially gluzincins, has been characterized functionally and structurally. The functional results, the determination of preliminary IC50 values by the use of an intramolecular quenched-fluorescence fluorogenic peptide assay, indicate that phosphoramidon inhibits ZMPSTE24 in a manner consistent with competitive inhibition. The structural results, a 3.85 Å resolution X-ray crystal structure of a ZMPSTE24-phosphoramidon complex, indicate that the overall binding mode observed between phosphoramidon and soluble gluzincins is conserved. Based on the structural data, a significantly lower potency than that observed for soluble gluzincins such as thermolysin and neprilysin is predicted. These results strongly suggest a close relationship between soluble gluzincins and the integral membrane protein zinc metalloprotease ZMPSTE24.
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Affiliation(s)
- Brandon R. Goblirsch
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0886, USA
| | - Buenafe T. Arachea
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0886, USA
| | - Daniel J. Councell
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0886, USA
| | - Michael C. Wiener
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0886, USA
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13
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Membrane properties that shape the evolution of membrane enzymes. Curr Opin Struct Biol 2018; 51:80-91. [PMID: 29597094 DOI: 10.1016/j.sbi.2018.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 02/07/2023]
Abstract
Spectacular recent progress in structural biology has led to determination of the structures of many integral membrane enzymes that catalyze reactions in which at least one substrate also is membrane bound. A pattern of results seems to be emerging in which the active site chemistry of these enzymes is usually found to be analogous to what is observed for water soluble enzymes catalyzing the same reaction types. However, in light of the chemical, structural, and physical complexity of cellular membranes plus the presence of transmembrane gradients and potentials, these enzymes may be subject to membrane-specific regulatory mechanisms that are only now beginning to be uncovered. We review the membrane-specific environmental traits that shape the evolution of membrane-embedded biocatalysts.
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14
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Abstract
Ras converting enzyme 1 (Rce1) is an integral membrane endoprotease localized to the endoplasmic reticulum that mediates the cleavage of the carboxyl-terminal three amino acids from CaaX proteins, whose members play important roles in cell signaling processes. Examples include the Ras family of small GTPases, the γ-subunit of heterotrimeric GTPases, nuclear lamins, and protein kinases and phosphatases. CaaX proteins, especially Ras, have been implicated in cancer, and understanding the post-translational modifications of CaaX proteins would provide insight into their biological function and regulation. Many proteolytic mechanisms have been proposed for Rce1, but sequence alignment, mutational studies, topology, and recent crystallographic data point to a novel mechanism involving a glutamate-activated water and an oxyanion hole. Studies using in vivo and in vitro reporters of Rce1 activity have revealed that the enzyme cleaves only prenylated substrates and the identity of the a2 amino residue in the Ca1a2X sequence is most critical for recognition, preferring Ile, Leu, or Val. Substrate mimetics can be somewhat effective inhibitors of Rce1 in vitro. Small-molecule inhibitor discovery is currently limited by the lack of structural information on a eukaryotic enzyme, but a set of 8-hydroxyquinoline derivatives has demonstrated an ability to mislocalize all three mammalian Ras isoforms, giving optimism that potent, selective inhibitors might be developed. Much remains to be discovered regarding cleavage specificity, the impact of chemical inhibition, and the potential of Rce1 as a therapeutic target, not only for cancer, but also for other diseases.
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Affiliation(s)
| | - Timothy M Dore
- a New York University Abu Dhabi , Abu Dhabi , United Arab Emirates.,b Department of Chemistry , University of Georgia , Athens , GA , USA
| | - Walter K Schmidt
- c Department of Biochemistry & Molecular Biology , University of Georgia , Athens , GA , USA
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15
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Li S, Fu B, Wang L, Dorf ME. ZMPSTE24 Is Downstream Effector of Interferon-Induced Transmembrane Antiviral Activity. DNA Cell Biol 2017; 36:513-517. [PMID: 28594571 DOI: 10.1089/dna.2017.3791] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The zinc metalloprotease ZMPSTE24 is a constitutively and ubiquitously expressed host restriction factor that is responsible for limiting infection by a broad spectrum of enveloped viruses, including influenza A, vesicular stomatitis, zika, ebola, Sindbis, cowpox, and vaccinia viruses, but not murine leukemia or adenovirus. Antiviral function is independent of ZMPSTE24 enzymatic activity. Protein interaction and genetic complementation studies indicate that ZMPSTE24 is a component of a common antiviral pathway that is associated with interferon-induced transmembrane proteins. In vivo studies with zmpste24-deficient mice demonstrate the importance of ZMPSTE24 for antiviral defense.
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Affiliation(s)
- Shitao Li
- 1 Department of Physiological Sciences, Oklahoma State University , Stillwater, Oklahoma
| | - Bishi Fu
- 2 Department of Microbiology and Immunobiology, Harvard Medical School , Boston, Massachusetts.,3 College of Life Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Lingyan Wang
- 1 Department of Physiological Sciences, Oklahoma State University , Stillwater, Oklahoma
| | - Martin E Dorf
- 2 Department of Microbiology and Immunobiology, Harvard Medical School , Boston, Massachusetts
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16
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Fu B, Wang L, Li S, Dorf ME. ZMPSTE24 defends against influenza and other pathogenic viruses. J Exp Med 2017; 214:919-929. [PMID: 28246125 PMCID: PMC5379977 DOI: 10.1084/jem.20161270] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 11/10/2016] [Accepted: 01/25/2017] [Indexed: 12/24/2022] Open
Abstract
Fu et al. show that ZMPSTE24 is a broad-spectrum antiviral protein that inhibits entry of selected fusogenic viruses by functioning as an effector in the IFITM pathway. ZMPSTE24 protease activity is dispensable for viral restriction. In mice, ZMPSTE24 deficiency increases susceptibility to influenza infection. Zinc metallopeptidase STE24 (ZMPSTE24) is a transmembrane metalloprotease whose catalytic activity is critical for processing lamin A on the inner nuclear membrane and clearing clogged translocons on the endoplasmic reticulum. We now report ZMPSTE24 is a virus-specific effector that restricts enveloped RNA and DNA viruses, including influenza A, Zika, Ebola, Sindbis, vesicular stomatitis, cowpox, and vaccinia, but not murine leukemia or adenovirus. ZMPSTE24-mediated antiviral action is independent of protease activity. Coimmunoprecipitation studies indicate ZMPSTE24 can complex with proteins of the interferon-induced transmembrane protein (IFITM) family. IFITM proteins impede viral entry, and ZMPSTE24 expression is necessary for IFITM antiviral activity. In vivo studies demonstrate ZMPSTE24-deficient mice display higher viral burdens, enhanced cytokine production, and increased mortality after influenza infection. Collectively, these findings identify ZMPSTE24 as an intrinsic broad-spectrum antiviral protein and provide insights into antiviral defense mechanisms.
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Affiliation(s)
- Bishi Fu
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115
| | - Lingyan Wang
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078
| | - Shitao Li
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078
| | - Martin E Dorf
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115
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17
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Arachea BT, Wiener MC. Acquisition of accurate data from intramolecular quenched fluorescence protease assays. Anal Biochem 2017; 522:30-36. [PMID: 28119065 DOI: 10.1016/j.ab.2017.01.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 10/20/2022]
Abstract
The Intramolecular Quenched Fluorescence (IQF) protease assay utilizes peptide substrates containing donor-quencher pairs that flank the scissile bond. Following protease cleavage, the dequenched donor emission of the product is subsequently measured. Inspection of the IQF literature indicates that rigorous treatment of systematic errors in observed fluorescence arising from inner-filter absorbance (IF) and non-specific intermolecular quenching (NSQ) is incompletely performed. As substrate and product concentrations vary during the time-course of enzyme activity, iterative solution of the kinetic rate equations is, generally, required to obtain the proper time-dependent correction to the initial velocity fluorescence data. Here, we demonstrate that, if the IQF assay is performed under conditions where IF and NSQ are approximately constant during the measurement of initial velocity for a given initial substrate concentration, then a simple correction as a function of initial substrate concentration can be derived and utilized to obtain accurate initial velocity data for analysis.
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Affiliation(s)
- Buenafe T Arachea
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Michael C Wiener
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.
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18
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Akinci B, Sankella S, Gilpin C, Ozono K, Garg A, Agarwal AK. Progeroid syndrome patients with ZMPSTE24 deficiency could benefit when treated with rapamycin and dimethylsulfoxide. Cold Spring Harb Mol Case Stud 2016; 3:a001339. [PMID: 28050601 PMCID: PMC5171694 DOI: 10.1101/mcs.a001339] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Patients with progeroid syndromes such as mandibuloacral dysplasia, type B (MADB) and restrictive dermopathy (RD) harbor mutations in zinc metalloproteinase (ZMPSTE24), an enzyme essential for posttranslational proteolysis of prelamin A to form mature lamin A. Dermal fibroblasts from these patients show increased nuclear dysmorphology and reduced proliferation; however, the efficacy of various pharmacological agents in reversing these cellular phenotypes remains unknown. In this study, fibroblasts from MADB patients exhibited marked nuclear abnormalities and reduced proliferation that improved upon treatment with rapamycin and dimethylsulfoxide but not with other agents, including farnesyl transferase inhibitors. Surprisingly, fibroblasts from an RD patient with a homozygous null mutation in ZMPSTE24, resulting in exclusive accumulation of prelamin A with no lamin A on immunoblotting of cellular lysate, exhibited few nuclear abnormalities and near-normal cellular proliferation. An unbiased proteomic analysis of the cellular lysate from RD fibroblasts revealed a lack of processing of vimentin, a cytoskeletal protein. Interestingly, the assembly of the vimentin microfibrils in MADB fibroblasts improved with rapamycin and dimethylsulfoxide. We conclude that rapamycin and dimethylsulfoxide are beneficial for improving nuclear morphology and cell proliferation of MADB fibroblasts. Data from a single RD patient's fibroblasts also suggest that prelamin A accumulation by itself might not be detrimental and requires additional alterations at the cellular level to manifest the phenotype.
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Affiliation(s)
- Baris Akinci
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Shireesha Sankella
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Christopher Gilpin
- Molecular and Cellular Imaging, Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Abhimanyu Garg
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Anil K Agarwal
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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19
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Hildebrandt ER, Cheng M, Zhao P, Kim JH, Wells L, Schmidt WK. A shunt pathway limits the CaaX processing of Hsp40 Ydj1p and regulates Ydj1p-dependent phenotypes. eLife 2016; 5. [PMID: 27525482 PMCID: PMC5014548 DOI: 10.7554/elife.15899] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 08/14/2016] [Indexed: 11/21/2022] Open
Abstract
The modifications occurring to CaaX proteins have largely been established using few reporter molecules (e.g. Ras, yeast a-factor mating pheromone). These proteins undergo three coordinated COOH-terminal events: isoprenylation of the cysteine, proteolytic removal of aaX, and COOH-terminal methylation. Here, we investigated the coupling of these modifications in the context of the yeast Ydj1p chaperone. We provide genetic, biochemical, and biophysical evidence that the Ydj1p CaaX motif is isoprenylated but not cleaved and carboxylmethylated. Moreover, we demonstrate that Ydj1p-dependent thermotolerance and Ydj1p localization are perturbed when alternative CaaX motifs are transplanted onto Ydj1p. The abnormal phenotypes revert to normal when post-isoprenylation events are genetically interrupted. Our findings indicate that proper Ydj1p function requires an isoprenylatable CaaX motif that is resistant to post-isoprenylation events. These results expand on the complexity of protein isoprenylation and highlight the impact of post-isoprenylation events in regulating the function of Ydj1p and perhaps other CaaX proteins. DOI:http://dx.doi.org/10.7554/eLife.15899.001
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Affiliation(s)
- Emily R Hildebrandt
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
| | - Michael Cheng
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
| | - Peng Zhao
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
| | - June H Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
| | - Walter K Schmidt
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
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