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Lutz A, Jung D, Diem K, Fauler M, Port F, Gottschalk K, Felder E. Acute effects of cell stretch on keratin filaments in A549 lung cells. FASEB J 2020; 34:11227-11242. [PMID: 32632966 DOI: 10.1096/fj.201903160rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 05/29/2020] [Accepted: 06/18/2020] [Indexed: 12/31/2022]
Abstract
Keratin filaments (KFs) comprise the intermediate filaments of epithelial cells and are well known for their cytoprotective properties and their mechanical resilience. Although, several studies have demonstrated KFs' remarkable tensile properties relatively little is known about acute implications of mechanical stretch on KFs in living cells. This includes structural effects on the KFs and their higher level assembly structures as well as posttranslational response mechanisms to possibly modify KF's properties. We subjected simple epithelial A549 lung cells to 30% unidirectional stretch and already after 10 seconds we observed morphological changes of the KF-network as well as structural effects on their desmosomal anchor sites-both apparently caused by the tensile strain. Interestingly, the effect on the desmosomes was attenuated after 30 seconds of cell stretch with a concomitant increase in phosphorylation of keratin8-S432, keratin18-S53, and keratin18-S34 without an apparent increase in keratin solubility. When mimicking the phosphorylation of keratin18-S34 the stretch-induced effect on the desmosomes could be diminished and probing the cell surface with atomic force microscopy showed a lowered elastic modulus. We conclude that the stretch-induced KF phosphorylation affects KF's tensile properties, probably to lower the mechanical load on strained desmosomal cell-cell contacts, and hence, preserve epithelial integrity.
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Affiliation(s)
- Anngrit Lutz
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Dominik Jung
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Kathrin Diem
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Michael Fauler
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Fabian Port
- Department of Experimental Physics, Ulm University, Ulm, Germany
| | - Kay Gottschalk
- Department of Experimental Physics, Ulm University, Ulm, Germany
| | - Edward Felder
- Department of General Physiology, Ulm University, Ulm, Germany
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Protein Phosphorylation in Serine Residues Correlates with Progression from Precancerous Lesions to Cervical Cancer in Mexican Patients. BIOMED RESEARCH INTERNATIONAL 2020; 2020:5058928. [PMID: 32337254 PMCID: PMC7157794 DOI: 10.1155/2020/5058928] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/12/2020] [Indexed: 12/24/2022]
Abstract
Protein phosphorylation is a posttranslational modification that is essential for normal cellular processes; however, abnormal phosphorylation is one of the prime causes for alteration of many structural, functional, and regulatory proteins in disease conditions. In cancer, changes in the states of protein phosphorylation in tyrosine residues have been more studied than phosphorylation in threonine or serine residues, which also undergo alterations with greater predominance. In general, serine phosphorylation leads to the formation of multimolecular signaling complexes that regulate diverse biological processes, but in pathological conditions such as tumorigenesis, anomalous phosphorylation may result in the deregulation of some signaling pathways. Cervical cancer (CC), the main neoplasm associated with human papillomavirus (HPV) infection, is the fourth most frequent cancer worldwide. Persistent infection of the cervix with high-risk human papillomaviruses produces precancerous lesions starting with low-grade squamous intraepithelial lesions (LSIL), progressing to high-grade squamous intraepithelial lesions (HSIL) until CC is generated. Here, we compared the proteomic profile of phosphorylated proteins in serine residues from healthy, LSIL, HSIL, and CC samples. Our data show an increase in the number of phosphorylated proteins in serine residues as the grade of injury rises. These results provide a support for future studies focused on phosphorylated proteins and their possible correlation with the progression of cervical lesions.
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Al-Maleki AR, Loke MF, Lui SY, Ramli NSK, Khosravi Y, Ng CG, Venkatraman G, Goh KL, Ho B, Vadivelu J. Helicobacter pylori outer inflammatory protein A (OipA) suppresses apoptosis of AGS gastric cells in vitro. Cell Microbiol 2017; 19. [PMID: 28776327 DOI: 10.1111/cmi.12771] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 07/02/2017] [Accepted: 07/26/2017] [Indexed: 12/12/2022]
Abstract
Outer inflammatory protein A (OipA) is an important virulence factor associated with gastric cancer and ulcer development; however, the results have not been well established and turned out to be controversial. This study aims to elucidate the role of OipA in Helicobacter pylori infection using clinical strains harbouring oipA "on" and "off" motifs. Proteomics analysis was performed on AGS cell pre-infection and postinfection with H. pylori oipA "on" and "off" strains, using liquid chromatography/mass spectrometry. AGS apoptosis and cell cycle assays were performed. Moreover, expression of vacuolating cytotoxin A (VacA) was screened using Western blotting. AGS proteins that have been suggested previously to play a role or associated with gastric disease were down-regulated postinfection with oipA "off" strains comparing to oipA "on" strains. Furthermore, oipA "off" and ΔoipA cause higher level of AGS cells apoptosis and G0/G1 cell-cycle arrest than oipA "on" strains. Interestingly, deletion of oipA increased bacterial VacA production. The capability of H. pylori to induce apoptosis and suppress expression of proteins having roles in human disease in the absence of oipA suggests that strains not expressing OipA may be less virulent or may even be protective against carcinogenesis compared those expressing OipA. This potentially explains the higher incidence of gastric cancer in East Asia where oipA "on" strains predominates.
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Affiliation(s)
- Anis Rageh Al-Maleki
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mun Fai Loke
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sook Yin Lui
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Nur Siti Khadijah Ramli
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yalda Khosravi
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chow Goon Ng
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Gopinath Venkatraman
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Khean-Lee Goh
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Bow Ho
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Singapore Precision Medicine Centre Pte Ltd, Singapore, Singapore
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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