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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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Du J, Wang X, Dong CH, Yang JM, Yao XJ. Computational Study of the Binding Mechanism of Actin-Depolymerizing Factor 1 with Actin in Arabidopsis thaliana. PLoS One 2016; 11:e0159053. [PMID: 27414648 PMCID: PMC4944973 DOI: 10.1371/journal.pone.0159053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/27/2016] [Indexed: 12/15/2022] Open
Abstract
Actin is a highly conserved protein. It plays important roles in cellular function and exists either in the monomeric (G-actin) or polymeric form (F-actin). Members of the actin-depolymerizing factor (ADF)/cofilin protein family bind to both G-actin and F-actin and play vital roles in actin dynamics by manipulating the rates of filament polymerization and depolymerization. It has been reported that the S6D and R98A/K100A mutants of actin-depolymerizing factor 1 (ADF1) in Arabidopsis thaliana decreased the binding affinity of ADF for the actin monomer. To investigate the binding mechanism and dynamic behavior of the ADF1–actin complex, we constructed a homology model of the AtADF1–actin complex based on the crystal structure of AtADF1 and the twinfilin C-terminal ADF-H domain in a complex with a mouse actin monomer. The model was then refined for subsequent molecular dynamics simulations. Increased binding energy of the mutated system was observed using the Molecular Mechanics Generalized Born Surface Area and Poisson–Boltzmann Surface Area (MM-GB/PBSA) methods. To determine the residues that make decisive contributions to the ADF1 actin-binding affinity, per-residue decomposition and computational alanine scanning analyses were performed, which provided more detailed information on the binding mechanism. Root-mean-square fluctuation and principal component analyses confirmed that the S6D and R98A/K100A mutants induced an increased conformational flexibility. The comprehensive molecular insight gained from this study is of great importance for understanding the binding mechanism of ADF1 and G-actin.
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Affiliation(s)
- Juan Du
- Key Laboratory of Plant Biotechnology of Shandong Province, College of Life Science, Qingdao Agricultural University, Qingdao, China
- * E-mail:
| | - Xue Wang
- Key Laboratory of Plant Biotechnology of Shandong Province, College of Life Science, Qingdao Agricultural University, Qingdao, China
| | - Chun-Hai Dong
- Key Laboratory of Plant Biotechnology of Shandong Province, College of Life Science, Qingdao Agricultural University, Qingdao, China
| | - Jian Ming Yang
- Key Laboratory of Plant Biotechnology of Shandong Province, College of Life Science, Qingdao Agricultural University, Qingdao, China
| | - Xiao Jun Yao
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China
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Roy-Zokan EM, Dyer KA, Meagher RB. Phylogenetic Patterns of Codon Evolution in the ACTIN-DEPOLYMERIZING FACTOR/COFILIN (ADF/CFL) Gene Family. PLoS One 2015; 10:e0145917. [PMID: 26717562 PMCID: PMC4696841 DOI: 10.1371/journal.pone.0145917] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/10/2015] [Indexed: 11/18/2022] Open
Abstract
The actin-depolymerizing factor/cofilin (ADF/CFL) gene family encodes a diverse group of relatively small proteins. Once known strictly as modulators of actin filament dynamics, recent research has demonstrated that these proteins are involved in a variety of cellular processes, from signal transduction to the cytonuclear trafficking of actin. In both plant and animal lineages, expression patterns of paralogs in the ADF/CFL gene family vary among tissue types and developmental stages. In this study we use computational approaches to investigate the evolutionary forces responsible for the diversification of the ADF/CFL gene family. Estimating the rate of non-synonymous to synonymous mutations (dN/dS) across phylogenetic lineages revealed that the majority of ADF/CFL codon positions were under strong purifying selection, with rare episodic events of accelerated protein evolution. In both plants and animals these instances of accelerated evolution were ADF/CFL subclass specific, and all of the sites under selection were located in regions of the protein that could serve in new functional roles. We suggest these sites may have been important in the functional diversification of ADF/CFL proteins.
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Affiliation(s)
- Eileen M. Roy-Zokan
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
| | - Kelly A. Dyer
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Richard B. Meagher
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
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