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Palma MS, Perez SR, Husain A, Bhandari D. Substrate preference of protein kinase B isoforms can vary depending on the cell line. PLoS One 2024; 19:e0298322. [PMID: 38502658 PMCID: PMC10950239 DOI: 10.1371/journal.pone.0298322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 01/22/2024] [Indexed: 03/21/2024] Open
Abstract
Many proteins in higher eukaryotes, especially those with crucial functions, have multiple isoforms with redundant roles providing protection against potential functional deficiencies in one isoform. However, these isoforms can also have some unique roles. Protein kinase B, also known as Akt, is one such protein that has three isoforms encoded on different genes. Due to high sequence similarity and the general lack of specific reagents, most studies on Akt generalize their findings and do not distinguish between the isoforms. Using an established chemical genetic strategy and a set of known Akt substrates, this work explores substrate specificity of Akt isoforms under steady state conditions in two commonly used cell lines. This strategy can be applied to study any Akt isoform-specific substrates of interest in any cell line of choice as long as the cell line can be transfected.
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Affiliation(s)
- Miguel S. Palma
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
| | - Samantha R. Perez
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
| | - Aida Husain
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
| | - Deepali Bhandari
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
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Irnaten M, O’Brien CJ. Calcium-Signalling in Human Glaucoma Lamina Cribrosa Myofibroblasts. Int J Mol Sci 2023; 24:ijms24021287. [PMID: 36674805 PMCID: PMC9862249 DOI: 10.3390/ijms24021287] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/20/2022] [Accepted: 01/01/2023] [Indexed: 01/11/2023] Open
Abstract
Glaucoma is one of the most common causes of treatable visual impairment in the developed world, affecting approximately 64 million people worldwide, some of whom will be bilaterally blind from irreversible optic nerve damage. The optic nerve head is a key site of damage in glaucoma where there is fibrosis of the connective tissue in the lamina cribrosa (LC) extracellular matrix. As a ubiquitous second messenger, calcium (Ca2+) can interact with various cellular proteins to regulate multiple physiological processes and contribute to a wide range of diseases, including cancer, fibrosis, and glaucoma. Our research has shown evidence of oxidative stress, mitochondrial dysfunction, an elevated expression of Ca2+ entry channels, Ca2+-dependent pumps and exchangers, and an abnormal rise in cytosolic Ca2+ in human glaucomatous LC fibroblast cells. We have evidence that this increase is dependent on Ca2+ entry channels located in the plasma membrane, and its release is from internal stores in the endoplasmic reticulum (ER), as well as from the mitochondria. Here, we summarize some of the molecular Ca2+-dependent mechanisms related to this abnormal Ca2+-signalling in human glaucoma LC cells, with a view toward identifying potential therapeutic targets for ongoing optic neuropathy.
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Vrijsen S, Vrancx C, Del Vecchio M, Swinnen JV, Agostinis P, Winderickx J, Vangheluwe P, Annaert W. Inter-organellar Communication in Parkinson's and Alzheimer's Disease: Looking Beyond Endoplasmic Reticulum-Mitochondria Contact Sites. Front Neurosci 2022; 16:900338. [PMID: 35801175 PMCID: PMC9253489 DOI: 10.3389/fnins.2022.900338] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 05/05/2022] [Indexed: 01/13/2023] Open
Abstract
Neurodegenerative diseases (NDs) are generally considered proteinopathies but whereas this may initiate disease in familial cases, onset in sporadic diseases may originate from a gradually disrupted organellar homeostasis. Herein, endolysosomal abnormalities, mitochondrial dysfunction, endoplasmic reticulum (ER) stress, and altered lipid metabolism are commonly observed in early preclinical stages of major NDs, including Parkinson's disease (PD) and Alzheimer's disease (AD). Among the multitude of underlying defective molecular mechanisms that have been suggested in the past decades, dysregulation of inter-organellar communication through the so-called membrane contact sites (MCSs) is becoming increasingly apparent. Although MCSs exist between almost every other type of subcellular organelle, to date, most focus has been put on defective communication between the ER and mitochondria in NDs, given these compartments are critical in neuronal survival. Contributions of other MCSs, notably those with endolysosomes and lipid droplets are emerging, supported as well by genetic studies, identifying genes functionally involved in lysosomal homeostasis. In this review, we summarize the molecular identity of the organelle interactome in yeast and mammalian cells, and critically evaluate the evidence supporting the contribution of disturbed MCSs to the general disrupted inter-organellar homeostasis in NDs, taking PD and AD as major examples.
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Affiliation(s)
- Stephanie Vrijsen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, KU Leuven, Leuven, Belgium
| | - Céline Vrancx
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Mara Del Vecchio
- Laboratory of Functional Biology, Department of Biology, KU Leuven, Heverlee, Belgium
| | - Johannes V. Swinnen
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, Leuven Cancer Institute (LKI), KU Leuven, Leuven, Belgium
| | - Patrizia Agostinis
- Laboratory of Cell Death Research and Therapy, VIB-Center for Cancer Research, KU Leuven, Leuven, Belgium
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Joris Winderickx
- Laboratory of Functional Biology, Department of Biology, KU Leuven, Heverlee, Belgium
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, KU Leuven, Leuven, Belgium
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
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Limso C, Ngo JM, Nguyen P, Leal S, Husain A, Sahoo D, Ghosh P, Bhandari D. The Gα-interacting vesicle-associated protein interacts with and promotes cell surface localization of GRP78 during endoplasmic reticulum stress. FEBS Lett 2019; 594:1088-1100. [PMID: 31736058 DOI: 10.1002/1873-3468.13685] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 11/07/2019] [Accepted: 11/12/2019] [Indexed: 12/18/2022]
Abstract
Cell surface translocation of the chaperone glucose-regulated protein 78 kDa (GRP78) is a key event that promotes cancer cell survival during endoplasmic reticulum (ER) stress. Here, we identify Gα-interacting vesicle-associated protein (GIV) - an enhancer of prosurvival signaling during ER stress - as a binding partner of GRP78. We show that GIV and GRP78 interact in an ER stress-dependent manner through their respective carboxyl terminal domains and that GIV aids in the localization of GRP78 to the plasma membrane. Kaplan-Meier analysis of disease-free survival in cancer patients shows poor prognosis for patients with high expression of both GIV and GRP78, further suggesting a vital role for these two proteins in enhancing cancer cell viability.
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Affiliation(s)
- Clariss Limso
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, USA
| | - Jordan Matthew Ngo
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, USA
| | - Peter Nguyen
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, USA
| | - Stephanie Leal
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, USA
| | - Aida Husain
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, USA
| | - Debashis Sahoo
- Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA, USA.,Department of Pediatrics, University of California San Diego, La Jolla, CA, USA
| | - Pradipta Ghosh
- Department of Medicine, University of California San Diego, La Jolla, CA, USA.,Department of Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Deepali Bhandari
- Department of Chemistry and Biochemistry, California State University Long Beach, CA, USA
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