1
|
Koukos PI, Dehghani-Ghahnaviyeh S, Velez-Vega C, Manchester J, Tieleman DP, Duca JS, Souza PCT, Cournia Z. Martini 3 Force Field Parameters for Protein Lipidation Post-Translational Modifications. J Chem Theory Comput 2023; 19:8901-8918. [PMID: 38019969 DOI: 10.1021/acs.jctc.3c00604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Protein lipidations are vital co/post-translational modifications that tether lipid tails to specific protein amino acids, allowing them to anchor to biological membranes, switch their subcellular localization, and modulate association with other proteins. Such lipidations are thus crucial for multiple biological processes including signal transduction, protein trafficking, and membrane localization and are implicated in various diseases as well. Examples of lipid-anchored proteins include the Ras family of proteins that undergo farnesylation; actin and gelsolin that are myristoylated; phospholipase D that is palmitoylated; glycosylphosphatidylinositol-anchored proteins; and others. Here, we develop parameters for cysteine-targeting farnesylation, geranylgeranylation, and palmitoylation, as well as glycine-targeting myristoylation for the latest version of the Martini 3 coarse-grained force field. The parameters are developed using the CHARMM36m all-atom force field parameters as reference. The behavior of the coarse-grained models is consistent with that of the all-atom force field for all lipidations and reproduces key dynamical and structural features of lipid-anchored peptides, such as the solvent-accessible surface area, bilayer penetration depth, and representative conformations of the anchors. The parameters are also validated in simulations of the lipid-anchored peripheral membrane proteins Rheb and Arf1, after comparison with independent all-atom simulations. The parameters, along with mapping schemes for the popular martinize2 tool, are available for download at 10.5281/zenodo.7849262 and also as supporting information.
Collapse
Affiliation(s)
- Panagiotis I Koukos
- Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou, 11527 Athens, Greece
| | - Sepehr Dehghani-Ghahnaviyeh
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Camilo Velez-Vega
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - John Manchester
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - D Peter Tieleman
- Department of Biological Sciences, University of Calgary, Calgary T2N 1N4 Alberta, Canada
- Centre for Molecular Simulation, University of Calgary, Calgary T2N 1N4 Alberta, Canada
| | - José S Duca
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Paulo C T Souza
- Molecular Microbiology and Structural Biochemistry, (MMSB, UMR 5086), CNRS & University of Lyon, 69367 Lyon, France
- Laboratory of Biology and Modeling of the Cell, École Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5239 and Inserm U1293, 46 Allée d'Italie, 69364 Lyon, France
| | - Zoe Cournia
- Biomedical Research Foundation, Academy of Athens, 4 Soranou Ephessiou, 11527 Athens, Greece
| |
Collapse
|
2
|
Araya MK, Gorfe AA. Conformational ensemble-dependent lipid recognition and segregation by prenylated intrinsically disordered regions in small GTPases. Commun Biol 2023; 6:1111. [PMID: 37919400 PMCID: PMC10622456 DOI: 10.1038/s42003-023-05487-6] [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: 05/15/2023] [Accepted: 10/19/2023] [Indexed: 11/04/2023] Open
Abstract
We studied diverse prenylated intrinsically disordered regions (PIDRs) of Ras and Rho family small GTPases using long timescale atomistic molecular dynamics simulations in an asymmetric model membrane of phosphatidylcholine (PC) and phosphatidylserine (PS) lipids. Here we show that conformational plasticity is a key determinant of lipid sorting by polybasic PIDRs and provide evidence for lipid sorting based on both headgroup and acyl chain structures. We further show that conformational ensemble-based lipid recognition is generalizable to all polybasic PIDRs, and that the sequence outside the polybasic domain (PBD) modulates the conformational plasticity, bilayer adsorption, and interactions of PIDRs with membrane lipids. Specifically, we find that palmitoylation, the ratio of basic to acidic residues, and the hydrophobic content of the sequence outside the PBD significantly impact the diversity of conformational substates and hence the extent of conformation-dependent lipid interactions. We thus propose that the PBD is required but not sufficient for the full realization of lipid sorting by prenylated PBD-containing membrane anchors, and that the membrane anchor is not only responsible for high affinity membrane binding but also directs the protein to the right target membrane where it participates in lipid sorting.
Collapse
Affiliation(s)
- Mussie K Araya
- McGovern Medical School, University of Texas Health Science Center at Houston, Department of Integrative Biology and Pharmacology, 6431 Fannin St., Houston, TX, 77030, USA
| | - Alemayehu A Gorfe
- McGovern Medical School, University of Texas Health Science Center at Houston, Department of Integrative Biology and Pharmacology, 6431 Fannin St., Houston, TX, 77030, USA.
- Biochemistry and Cell Biology Program & Therapeutics and Pharmacology Program, UTHealth MD Anderson Cancer Center Graduate School of Biomedical Sciences, Houston, 6431 Fannin St., TX, 77030, USA.
| |
Collapse
|
3
|
Mosaddeghzadeh N, Nouri K, Krumbach OHF, Amin E, Dvorsky R, Ahmadian MR. Selectivity Determinants of RHO GTPase Binding to IQGAPs. Int J Mol Sci 2021; 22:12596. [PMID: 34830479 PMCID: PMC8625570 DOI: 10.3390/ijms222212596] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 12/13/2022] Open
Abstract
IQ motif-containing GTPase-activating proteins (IQGAPs) modulate a wide range of cellular processes by acting as scaffolds and driving protein components into distinct signaling networks. Their functional states have been proposed to be controlled by members of the RHO family of GTPases, among other regulators. In this study, we show that IQGAP1 and IQGAP2 can associate with CDC42 and RAC1-like proteins but not with RIF, RHOD, or RHO-like proteins, including RHOA. This seems to be based on the distribution of charged surface residues, which varies significantly among RHO GTPases despite their high sequence homology. Although effector proteins bind first to the highly flexible switch regions of RHO GTPases, additional contacts outside are required for effector activation. Sequence alignment and structural, mutational, and competitive biochemical analyses revealed that RHO GTPases possess paralog-specific residues outside the two highly conserved switch regions that essentially determine the selectivity of RHO GTPase binding to IQGAPs. Amino acid substitution of these specific residues in RHOA to the corresponding residues in RAC1 resulted in RHOA association with IQGAP1. Thus, electrostatics most likely plays a decisive role in these interactions.
Collapse
Affiliation(s)
- Niloufar Mosaddeghzadeh
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.M.); (K.N.); (O.H.F.K.); (E.A.); (R.D.)
| | - Kazem Nouri
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.M.); (K.N.); (O.H.F.K.); (E.A.); (R.D.)
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Oliver H. F. Krumbach
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.M.); (K.N.); (O.H.F.K.); (E.A.); (R.D.)
| | - Ehsan Amin
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.M.); (K.N.); (O.H.F.K.); (E.A.); (R.D.)
- Medical Faculty, Institute of Neural and Sensory Physiology, University Hospital Düsseldorf, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Radovan Dvorsky
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.M.); (K.N.); (O.H.F.K.); (E.A.); (R.D.)
| | - Mohammad R. Ahmadian
- Medical Faculty, Institute of Biochemistry and Molecular Biology II, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (N.M.); (K.N.); (O.H.F.K.); (E.A.); (R.D.)
| |
Collapse
|
4
|
Zhou Y, Hancock JF. Lipid Profiles of RAS Nanoclusters Regulate RAS Function. Biomolecules 2021; 11:biom11101439. [PMID: 34680072 PMCID: PMC8533076 DOI: 10.3390/biom11101439] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/12/2022] Open
Abstract
The lipid-anchored RAS (Rat sarcoma) small GTPases (guanosine triphosphate hydrolases) are highly prevalent in human cancer. Traditional strategies of targeting the enzymatic activities of RAS have been shown to be difficult. Alternatively, RAS function and pathology are mostly restricted to nanoclusters on the plasma membrane (PM). Lipids are important structural components of these signaling platforms on the PM. However, how RAS nanoclusters selectively enrich distinct lipids in the PM, how different lipids contribute to RAS signaling and oncogenesis and whether the selective lipid sorting of RAS nanoclusters can be targeted have not been well-understood. Latest advances in quantitative super-resolution imaging and molecular dynamic simulations have allowed detailed characterization RAS/lipid interactions. In this review, we discuss the latest findings on the select lipid composition (with headgroup and acyl chain specificities) within RAS nanoclusters, the specific mechanisms for the select lipid sorting of RAS nanoclusters on the PM and how perturbing lipid compositions within RAS nanoclusters impacts RAS function and pathology. We also describe different strategies of manipulating lipid composition within RAS nanoclusters on the PM.
Collapse
|
5
|
Rio-Vilariño A, del Puerto-Nevado L, García-Foncillas J, Cebrián A. Ras Family of Small GTPases in CRC: New Perspectives for Overcoming Drug Resistance. Cancers (Basel) 2021; 13:3757. [PMID: 34359657 PMCID: PMC8345156 DOI: 10.3390/cancers13153757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/20/2021] [Accepted: 07/23/2021] [Indexed: 12/11/2022] Open
Abstract
Colorectal cancer remains among the cancers with the highest incidence, prevalence, and mortality worldwide. Although the development of targeted therapies against the EGFR and VEGFR membrane receptors has considerably improved survival in these patients, the appearance of resistance means that their success is still limited. Overactivation of several members of the Ras-GTPase family is one of the main actors in both tumour progression and the lack of response to cytotoxic and targeted therapies. This fact has led many resources to be devoted over the last decades to the development of targeted therapies against these proteins. However, they have not been as successful as expected in their move to the clinic so far. In this review, we will analyse the role of these Ras-GTPases in the emergence and development of colorectal cancer and their relationship with resistance to targeted therapies, as well as the status and new advances in the design of targeted therapies against these proteins and their possible clinical implications.
Collapse
Affiliation(s)
| | | | - Jesús García-Foncillas
- Translational Oncology Division, Hospital Universitario Fundación Jimenez Diaz, 28040 Madrid, Spain; (A.R.-V.); (L.d.P.-N.)
| | - Arancha Cebrián
- Translational Oncology Division, Hospital Universitario Fundación Jimenez Diaz, 28040 Madrid, Spain; (A.R.-V.); (L.d.P.-N.)
| |
Collapse
|
6
|
Torres M, Rosselló CA, Fernández-García P, Lladó V, Kakhlon O, Escribá PV. The Implications for Cells of the Lipid Switches Driven by Protein-Membrane Interactions and the Development of Membrane Lipid Therapy. Int J Mol Sci 2020; 21:ijms21072322. [PMID: 32230887 PMCID: PMC7177374 DOI: 10.3390/ijms21072322] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 02/06/2023] Open
Abstract
The cell membrane contains a variety of receptors that interact with signaling molecules. However, agonist-receptor interactions not always activate a signaling cascade. Amphitropic membrane proteins are required for signal propagation upon ligand-induced receptor activation. These proteins localize to the plasma membrane or internal compartments; however, they are only activated by ligand-receptor complexes when both come into physical contact in membranes. These interactions enable signal propagation. Thus, signals may not propagate into the cell if peripheral proteins do not co-localize with receptors even in the presence of messengers. As the translocation of an amphitropic protein greatly depends on the membrane's lipid composition, regulation of the lipid bilayer emerges as a novel therapeutic strategy. Some of the signals controlled by proteins non-permanently bound to membranes produce dramatic changes in the cell's physiology. Indeed, changes in membrane lipids induce translocation of dozens of peripheral signaling proteins from or to the plasma membrane, which controls how cells behave. We called these changes "lipid switches", as they alter the cell's status (e.g., proliferation, differentiation, death, etc.) in response to the modulation of membrane lipids. Indeed, this discovery enables therapeutic interventions that modify the bilayer's lipids, an approach known as membrane-lipid therapy (MLT) or melitherapy.
Collapse
Affiliation(s)
- Manuel Torres
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, Ctra. de Valldemossa km 7.5, E-07122 Palma, Spain; (M.T.); (C.A.R.); (P.F.-G.); (V.L.)
- Department of R&D, Laminar Pharmaceuticals SL. ParcBit, Ed. Naorte B, E-07121 Palma, Spain
| | - Catalina Ana Rosselló
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, Ctra. de Valldemossa km 7.5, E-07122 Palma, Spain; (M.T.); (C.A.R.); (P.F.-G.); (V.L.)
- Department of R&D, Laminar Pharmaceuticals SL. ParcBit, Ed. Naorte B, E-07121 Palma, Spain
| | - Paula Fernández-García
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, Ctra. de Valldemossa km 7.5, E-07122 Palma, Spain; (M.T.); (C.A.R.); (P.F.-G.); (V.L.)
- Department of R&D, Laminar Pharmaceuticals SL. ParcBit, Ed. Naorte B, E-07121 Palma, Spain
| | - Victoria Lladó
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, Ctra. de Valldemossa km 7.5, E-07122 Palma, Spain; (M.T.); (C.A.R.); (P.F.-G.); (V.L.)
- Department of R&D, Laminar Pharmaceuticals SL. ParcBit, Ed. Naorte B, E-07121 Palma, Spain
| | - Or Kakhlon
- Department of Neurology, Hadassah-Hebrew University Medical Center, Ein Kerem, 91120 Jerusalem, Israel;
| | - Pablo Vicente Escribá
- Laboratory of Molecular Cell Biomedicine, Department of Biology, University of the Balearic Islands, Ctra. de Valldemossa km 7.5, E-07122 Palma, Spain; (M.T.); (C.A.R.); (P.F.-G.); (V.L.)
- Correspondence:
| |
Collapse
|
7
|
Abdelkarim H, Banerjee A, Grudzien P, Leschinsky N, Abushaer M, Gaponenko V. The Hypervariable Region of K-Ras4B Governs Molecular Recognition and Function. Int J Mol Sci 2019; 20:ijms20225718. [PMID: 31739603 PMCID: PMC6888304 DOI: 10.3390/ijms20225718] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/09/2019] [Accepted: 11/11/2019] [Indexed: 12/25/2022] Open
Abstract
The flexible C-terminal hypervariable region distinguishes K-Ras4B, an important proto-oncogenic GTPase, from other Ras GTPases. This unique lysine-rich portion of the protein harbors sites for post-translational modification, including cysteine prenylation, carboxymethylation, phosphorylation, and likely many others. The functions of the hypervariable region are diverse, ranging from anchoring K-Ras4B at the plasma membrane to sampling potentially auto-inhibitory binding sites in its GTPase domain and participating in isoform-specific protein-protein interactions and signaling. Despite much research, there are still many questions about the hypervariable region of K-Ras4B. For example, mechanistic details of its interaction with plasma membrane lipids and with the GTPase domain require further clarification. The roles of the hypervariable region in K-Ras4B-specific protein-protein interactions and signaling are incompletely defined. It is also unclear why post-translational modifications frequently found in protein polylysine domains, such as acetylation, glycation, and carbamoylation, have not been observed in K-Ras4B. Expanding knowledge of the hypervariable region will likely drive the development of novel highly-efficient and selective inhibitors of K-Ras4B that are urgently needed by cancer patients.
Collapse
Affiliation(s)
- Hazem Abdelkarim
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago (UIC), Chicago, IL 60607, USA; (H.A.); (P.G.); (N.L.); (M.A.)
| | - Avik Banerjee
- Department of Chemistry, University of Illinois at Chicago (UIC), Chicago, IL 60612, USA;
| | - Patrick Grudzien
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago (UIC), Chicago, IL 60607, USA; (H.A.); (P.G.); (N.L.); (M.A.)
| | - Nicholas Leschinsky
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago (UIC), Chicago, IL 60607, USA; (H.A.); (P.G.); (N.L.); (M.A.)
| | - Mahmoud Abushaer
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago (UIC), Chicago, IL 60607, USA; (H.A.); (P.G.); (N.L.); (M.A.)
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago (UIC), Chicago, IL 60607, USA; (H.A.); (P.G.); (N.L.); (M.A.)
- Correspondence: ; Tel.: +312-355-4839
| |
Collapse
|
8
|
Kay JG, Fairn GD. Distribution, dynamics and functional roles of phosphatidylserine within the cell. Cell Commun Signal 2019; 17:126. [PMID: 31615534 PMCID: PMC6792266 DOI: 10.1186/s12964-019-0438-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 09/10/2019] [Indexed: 12/19/2022] Open
Abstract
Phosphatidylserine (PtdSer), an essential constituent of eukaryotic membranes, is the most abundant anionic phospholipid in the eukaryotic cell accounting for up to 10% of the total cellular lipid. Much of what is known about PtdSer is the role exofacial PtdSer plays in apoptosis and blood clotting. However, PtdSer is generally not externally exposed in healthy cells and plays a vital role in several intracellular signaling pathways, though relatively little is known about the precise subcellular localization, transmembrane topology and intracellular dynamics of PtdSer within the cell. The recent development of new, genetically-encoded probes able to detect phosphatidylserine is leading to a more in-depth understanding of the biology of this phospholipid. This review aims to give an overview of recent developments in our understanding of the role of PtdSer in intracellular signaling events derived from the use of these recently developed methods of phosphatidylserine detection.
Collapse
Affiliation(s)
- Jason G Kay
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, 14214, USA.
| | - Gregory D Fairn
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, M5B 1W8, Canada. .,Department of Surgery, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| |
Collapse
|
9
|
Membrane Dynamics in Health and Disease: Impact on Cellular Signalling. J Membr Biol 2019; 252:213-226. [PMID: 31435696 DOI: 10.1007/s00232-019-00087-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 08/07/2019] [Indexed: 12/16/2022]
Abstract
Biological membranes display a staggering complexity of lipids and proteins orchestrating cellular functions. Superior analytical tools coupled with numerous functional cellular screens have enabled us to query their role in cellular signalling, trafficking, guiding protein structure and function-all of which rely on the dynamic membrane lipid properties indispensable for proper cellular functions. Alteration of these has led to emergence of various pathological conditions, thus opening an area of lipid-centric therapeutic approaches. This perspective is a short summary of the dynamic properties of membranes essential for proper cellular functions, dictating both protein and lipid functions, and mis-regulated in diseases. Towards the end, we focus on some challenges lying ahead and potential means to tackle the same, mainly underscored by multi-disciplinary approaches.
Collapse
|
10
|
Wei L, Chang H, Huo S. Analyses on K-ras mutations and fascin expression in patients with cardia cancer. Oncol Lett 2018; 17:1807-1811. [PMID: 30675241 PMCID: PMC6341761 DOI: 10.3892/ol.2018.9750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 11/02/2018] [Indexed: 12/16/2022] Open
Abstract
Mutations of K-rat sarcoma (K-ras) in patients with cardia cancer and their effects on the expression of fascin were investigated. A total of 90 cardia cancer patients treated in Jining First People's Hospital from March 2014 to March 2017 were randomly selected. Genomic deoxyribonucleic acid (DNA) was extracted from paraffin-embedded cardia cancer specimens. Pyrosequencing was applied to detect sequences of K-ras gene in all patients and to analyze the mutations of K-ras gene. Then, genotyping of mutations at each mutation site was carried out using quantitative polymerase chain reaction (qPCR). The expression level of fascin in patients was measured via immunohistochemistry and qPCR. The results revealed that among 90 patients with cardia cancer, 21 patients had K-ras mutations (23.3%), including 20 cases of exon 12 mutation and 1 case of exon 13 mutation. Risk factor analyses revealed that alcohol abuse was a high risk factor for mutations (p<0.05). There was no significant difference in the mutation probability between heterozygotes and homozygotes for four mutations at codon 12 (p>0.05). The heterozygote at codon 13 had a higher mutation probability than homozygote (p<0.05). Immunohistochemistry suggested that the number of positive cells in the mutant group was larger than that in the non-mutant group (p<0.05). The results of qPCR showed that the expression level of fascin gene in the mutant group was 2.3 times higher than that in the non-mutant group (p<0.05). In conclusion, the probability of codon 12 mutation in K-ras gene is increased in patients with cardia cancer, and fascin is highly expressed in mutant patients, which is positively correlated with the mutations in K-ras gene.
Collapse
Affiliation(s)
- Li Wei
- Department of Pathology, Jining First People's Hospital, Jining, Shandong 272111, P.R. China
| | - Haiyan Chang
- Department of Gastrointestinal Surgery, Jining First People's Hospital, Jining, Shandong 272111, P.R. China
| | - Song Huo
- Department of Pathology, Jining Tumor Hospital, Jining, Shandong 272000, P.R. China
| |
Collapse
|
11
|
Zhou Y, Hancock JF. Deciphering lipid codes: K-Ras as a paradigm. Traffic 2018; 19:157-165. [PMID: 29120102 PMCID: PMC5927616 DOI: 10.1111/tra.12541] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 01/02/2023]
Abstract
The cell plasma membrane (PM) is a highly dynamic and heterogeneous lipid environment, driven by complex hydrophobic and electrostatic interactions among the hundreds of types of lipid species. Although the biophysical processes governing lipid lateral segregation in the cell PM have been established in vitro, biological implications of lipid heterogeneity are poorly understood. Of particular interest is how membrane proteins potentially utilize transient spatial clustering of PM lipids to regulate function. This review focuses on a lipid-anchored small GTPase K-Ras as an example to explore how its C-terminal membrane-anchoring domain, consisting of a contiguous hexa-lysine polybasic domain and an adjacent farnesyl anchor, possesses a complex coding mechanism for highly selective lipid sorting on the PM. How this lipid specificity modulates K-Ras signal transmission will also be discussed.
Collapse
Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX
| |
Collapse
|