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Khan K, Zafar S, Badshah Y, Ashraf NM, Rafiq M, Danish L, Shabbir M, Trembley JH, Afsar T, Almajwal A, Razak S. Cross talk of tumor protein D52 (TPD52) with KLF9, PKCε, and MicroRNA 223 in ovarian cancer. J Ovarian Res 2023; 16:202. [PMID: 37833790 PMCID: PMC10571360 DOI: 10.1186/s13048-023-01292-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 10/02/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND Gynecologic cancers comprise malignancies in the female reproductive organs. Ovarian cancer ranks sixth in terms of incidence rates while seventh in terms of mortality rates. The stage at which ovarian cancer is diagnosed mainly determines the survival outcomes of patients. Various screening approaches are presently employed for diagnosing ovarian cancer; however, these techniques have low accuracy and are non-specific, resulting in high mortality rates of patients due to this disease. Hence, it is crucial to identify improved screening and diagnostic markers to overcome this cancer. This study aimed to find new biomarkers to facilitate the prognosis and diagnosis of ovarian cancer. METHODS Bioinformatics approaches were used to predict the tertiary structure and cellular localization along with phylogenetic analysis of TPD52. Its molecular interactions were determined through KEGG analysis, and real-time PCR-based expression analysis was performed to assess its co-expression with another oncogenic cellular pathway (miR-223, KLF9, and PKCε) proteins in ovarian cancer. RESULTS Bioinformatics analysis depicted the cytoplasmic localization of TPD52 and the high conservation of its coiled-coil domains. Further study revealed that TPD52 mRNA and miRNA-223 expression was elevated, while the expression of KLF 9 and PKCε was reduced in the blood of ovarian cancer patients. Furthermore, TPD52 and miR-223 expression were upregulated in the early stages of cancer and non-metastatic cancers. CONCLUSION TPD52, miR-223, PKCε, and KLF9, can be used as a blood based markers for disease prognosis, metastasis, and treatment response. The study outcomes hold great potential to be translated at the clinical level after further validation on larger cohorts.
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Affiliation(s)
- Khushbukhat Khan
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, 44000, Pakistan
| | - Sameen Zafar
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, 44000, Pakistan
| | - Yasmin Badshah
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, 44000, Pakistan
| | - Naeem Mahmood Ashraf
- School of Biochemistry & Biotechnology, University of the Punjab, Lahore, Pakistan
| | - Mehak Rafiq
- School of Interdisciplinary Engineering & Sciences (SINES), National University of Sciences and Technology, Islamabad, 44000, Pakistan
| | - Lubna Danish
- Agricultural Research Institute, Tarnab, Peshawar, Pakistan
| | - Maria Shabbir
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, 44000, Pakistan.
- Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan.
| | - Janeen H Trembley
- Research Service, Minneapolis VA Health Care System, Minneapolis, MN, USA
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Tayyaba Afsar
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Ali Almajwal
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Suhail Razak
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
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Trehan D, Kumari R, Sharma J, Satuluri SH, Sahay S, Jha NK, Batra JK, Agrawal U. Inhibition of protein kinase C isozymes causes immune profile alteration and possibly decreased tumorigenesis in bladder cancer. Am J Cancer Res 2023; 13:3832-3852. [PMID: 37693140 PMCID: PMC10492116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/23/2023] [Indexed: 09/12/2023] Open
Abstract
Protein kinase C (PRKC) isozymes activate many signaling pathways and promote tumorigenesis, which can be confirmed by masking the kinase activity. In the present study, the kinase activity of PRKC ε and ζ isozymes was masked by siRNA in bladder cancer, and the consequent gene profile was evaluated. Here, we show that the commonly dysregulated genes affected by both the isozymes were the chemokines (CXCL8 & CXCL10), adhesion molecules (ICAM1, SPP1, MMP3, VEGFA) and mutated isoform of TP53. As these same genes were upregulated in bladder cancer patients, the activity of the kinase in downregulating them is confirmed. These genes are associated with regulating the tumor microenvironment, proliferation and differentiation of cancer cells and poor prognosis. The effect of kinase masking in downregulating these genes in bladder cancer indicates the benefits PRKC inhibitors may have in managing these patients.
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Affiliation(s)
- Deepika Trehan
- ICMR-National Institute of PathologyNew Delhi, India
- Jamia Hamdard UniversityNew Delhi, India
| | - Ranbala Kumari
- ICMR-National Institute of PathologyNew Delhi, India
- Amity UniversityNoida, UP, India
| | - Jyoti Sharma
- ICMR-National Institute of PathologyNew Delhi, India
| | | | - Satya Sahay
- ICMR-National Institute of PathologyNew Delhi, India
| | | | | | - Usha Agrawal
- ICMR-National Institute of PathologyNew Delhi, India
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Pozzi G, Presta V, Masselli E, Condello G, Cortellazzi S, Arcari ML, Micheloni C, Vitale M, Gobbi G, Mirandola P, Carubbi C. Interplay between Protein Kinase C Epsilon and Reactive Oxygen Species during Myogenic Differentiation. Cells 2023; 12:1792. [PMID: 37443826 PMCID: PMC10340168 DOI: 10.3390/cells12131792] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/22/2023] [Accepted: 06/30/2023] [Indexed: 07/15/2023] Open
Abstract
Reactive oxygen species (ROS) are currently recognized as a key driver of several physiological processes. Increasing evidence indicates that ROS levels can affect myogenic differentiation, but the molecular mechanisms still need to be elucidated. Protein kinase C (PKC) epsilon (PKCe) promotes muscle stem cell differentiation and regeneration of skeletal muscle after injury. PKCs play a tissue-specific role in redox biology, with specific isoforms being both a target of ROS and an up-stream regulator of ROS production. Therefore, we hypothesized that PKCe represents a molecular link between redox homeostasis and myogenic differentiation. We used an in vitro model of a mouse myoblast cell line (C2C12) to study the PKC-redox axis. We demonstrated that the transition from a myoblast to myotube is typified by increased PKCe protein content and decreased ROS. Intriguingly, the expression of the antioxidant enzyme superoxide dismutase 2 (SOD2) is significantly higher in the late phases of myogenic differentiation, mimicking PKCe protein content. Furthermore, we demonstrated that PKCe inhibition increases ROS and reduces SOD2 protein content while SOD2 silencing did not affect PKCe protein content, suggesting that the kinase could be an up-stream regulator of SOD2. To support this hypothesis, we found that in C2C12 cells, PKCe interacts with Nrf2, whose activation induces SOD2 transcription. Overall, our results indicate that PKCe is capable of activating the antioxidant signaling preventing ROS accumulation in a myotube, eventually promoting myogenic differentiation.
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Affiliation(s)
- Giulia Pozzi
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Valentina Presta
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Elena Masselli
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Giancarlo Condello
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Samuele Cortellazzi
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Maria Luisa Arcari
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Cristina Micheloni
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Marco Vitale
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
- Italian Foundation for Research in Balneotherapy (FoRST), 00198 Rome, Italy
| | - Giuliana Gobbi
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Prisco Mirandola
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
| | - Cecilia Carubbi
- Department of Medicine and Surgery (DiMeC), University of Parma, Via Gramsci, 14, 43126 Parma, Italy; (G.P.); (V.P.); (E.M.); (G.C.); (M.L.A.); (C.M.); (M.V.); (C.C.)
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Bogush D, Schramm J, Ding Y, He B, Singh C, Sharma A, Tukaramrao DB, Iyer S, Desai D, Nalesnik G, Hengst J, Bhalodia R, Gowda C, Dovat S. Signaling pathways and regulation of gene expression in hematopoietic cells. Adv Biol Regul 2023; 88:100942. [PMID: 36621151 DOI: 10.1016/j.jbior.2022.100942] [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: 11/16/2022] [Revised: 12/06/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Cellular functions are regulated by signal transduction pathway networks consisting of protein-modifying enzymes that control the activity of many downstream proteins. Protein kinases and phosphatases regulate gene expression by reversible phosphorylation of transcriptional factors, which are their direct substrates. Casein kinase II (CK2) is a serine/threonine kinase that phosphorylates a large number of proteins that have critical roles in cellular proliferation, metabolism and survival. Altered function of CK2 has been associated with malignant transformation, immunological disorders and other types of diseases. Protein phosphatase 1 (PP1) is a serine/threonine phosphatase, which regulates the phosphorylation status of many proteins that are essential for cellular functions. IKAROS is a DNA-binding protein, which functions as a regulator of gene transcription in hematopoietic cells. CK2 directly phosphorylates IKAROS at multiple phosphosites which determines IKAROS activity as a regulator of gene expression. PP1 binds to IKAROS via the PP1-consensus recognition site and dephosphorylates serine/threonine residues that are phosphorylated by CK2. Thus, the interplay between CK2 and PP1 signaling pathways have opposing effects on the phosphorylation status of their mutual substrate - IKAROS. This review summarizes the effects of CK2 and PP1 on IKAROS role in regulation of gene expression and its function as a tumor suppressor in leukemia.
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Affiliation(s)
- Daniel Bogush
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Joseph Schramm
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Yali Ding
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Bing He
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Chingakham Singh
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Arati Sharma
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | | | - Soumya Iyer
- University of Chicago, Chicago, IL, 60637, USA
| | - Dhimant Desai
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Gregory Nalesnik
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Jeremy Hengst
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Riya Bhalodia
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA
| | - Chandrika Gowda
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA.
| | - Sinisa Dovat
- Pennsylvania State University College of Medicine, Hershey, PA, 1703, USA.
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Lockwood N, Martini S, Lopez-Pardo A, Deiss K, Segeren HA, Semple RK, Collins I, Repana D, Cobbaut M, Soliman T, Ciccarelli F, Parker PJ. Genome-Protective Topoisomerase 2a-Dependent G2 Arrest Requires p53 in hTERT-Positive Cancer Cells. Cancer Res 2022; 82:1762-1773. [PMID: 35247890 PMCID: PMC7612711 DOI: 10.1158/0008-5472.can-21-1785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 02/01/2022] [Accepted: 02/25/2022] [Indexed: 11/16/2022]
Abstract
Topoisomerase 2a (Topo2a)-dependent G2 arrest engenders faithful segregation of sister chromatids, yet in certain tumor cell lines where this arrest is dysfunctional, a PKCε-dependent failsafe pathway can be triggered. Here we elaborate on recent advances in understanding the underlying mechanisms associated with this G2 arrest by determining that p53-p21 signaling is essential for efficient arrest in cell lines, in patient-derived cells, and in colorectal cancer organoids. Regulation of this p53 axis required the SMC5/6 complex, which is distinct from the p53 pathways observed in the DNA damage response. Topo2a inhibition specifically during S phase did not trigger G2 arrest despite affecting completion of DNA replication. Moreover, in cancer cells reliant upon the alternative lengthening of telomeres (ALT) mechanism, a distinct form of Topo2a-dependent, p53-independent G2 arrest was found to be mediated by BLM and Chk1. Importantly, the previously described PKCε-dependent mitotic failsafe was engaged in hTERT-positive cells when Topo2a-dependent G2 arrest was dysfunctional and where p53 was absent, but not in cells dependent on the ALT mechanism. In PKCε knockout mice, p53 deletion elicited tumors were less aggressive than in PKCε-replete animals and exhibited a distinct pattern of chromosomal rearrangements. This evidence suggests the potential of exploiting synthetic lethality in arrest-defective hTERT-positive tumors through PKCε-directed therapeutic intervention. SIGNIFICANCE The identification of a requirement for p53 in stringent Topo2a-dependent G2 arrest and engagement of PKCε failsafe pathways in arrest-defective hTERT-positive cells provides a therapeutic opportunity to induce selective synthetic lethality.
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Affiliation(s)
- Nicola Lockwood
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, London, UK
| | - Silvia Martini
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, London, UK
| | - Ainara Lopez-Pardo
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, London, UK
| | - Katharina Deiss
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, London, UK
| | - Hendrika A Segeren
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, London, UK
| | - Robert K Semple
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Ian Collins
- Division of Cancer Therapeutics, The Institute of Cancer Research, London, UK
| | - Dimitra Repana
- Cancer Systems Biology Laboratory, The Francis Crick Institute, London, UK.,School of Cancer and Pharmaceutical Sciences King's College London, New Hunt's House, Guy's Campus, London, UK
| | - Mathias Cobbaut
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, London, UK
| | - Tanya Soliman
- Barts Cancer Institute, Queen Mary University London, Charterhouse Square, London, UK
| | - Francesca Ciccarelli
- Cancer Systems Biology Laboratory, The Francis Crick Institute, London, UK.,School of Cancer and Pharmaceutical Sciences King's College London, New Hunt's House, Guy's Campus, London, UK
| | - Peter J Parker
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, London, UK.,School of Cancer and Pharmaceutical Sciences King's College London, New Hunt's House, Guy's Campus, London, UK
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OUP accepted manuscript. Hum Mol Genet 2022; 31:2236-2261. [DOI: 10.1093/hmg/ddac029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/22/2022] [Accepted: 01/24/2022] [Indexed: 11/12/2022] Open
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Khan K, Zafar S, Hafeez A, Badshah Y, Shahid K, Mahmood Ashraf N, Shabbir M. PRKCE non-coding variants influence on transcription as well as translation of its gene. RNA Biol 2022; 19:1115-1129. [PMID: 36299231 PMCID: PMC9621080 DOI: 10.1080/15476286.2022.2139110] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 10/31/2022] Open
Abstract
Untranslated regions of the gene play a crucial role in gene expression regulation at mRNA and protein levels. Mutations at UTRs impact expression by altering transcription factor binding, transcriptional/translational efficacy, miRNA-mediated gene regulation, mRNA secondary structure, ribosomal translocation, and stability. PKCε, a serine/threonine kinase, is aberrantly expressed in numerous diseases such as cardiovascular disorders, neurological disorders, and cancers; its probable cause is unknown. Therefore, in the current study, the influence of PRKCE 5'-and 3'UTR variants was explored for their potential impact on its transcription and translation through several bioinformatics approaches. UTR variants data was obtained through different databases and initially evaluated for their regulatory function. Variants with regulatory function were then studied for their effect on PRKCE binding with transcription factors (TF) and miRNAs, as well as their impact on mRNA secondary structure. Study outcomes indicated the regulatory function of 73 5'UTR and 17 3'UTR variants out of 376. 5'UTR variants introduced AP1 binding sites and promoted the PRKCE transcription. Four 3'UTR variants introduced a circular secondary structure, increasing PRKCE translational efficacy. A region in 5'UTR position 45,651,564 to 45,651,644 was found where variants readily influenced the miRNA-PRKCE mRNA binding. The study further highlighted a PKCε-regulated feedback loop mechanism that induces the activity of TFs, promoting its gene transcription. The study provides foundations for experimentation to understand these variants' role in diseases. These variants can also serve as the genetic markers for different diseases' diagnoses after validation at the cell and population levels.
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Affiliation(s)
- Khushbukhat Khan
- Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Sameen Zafar
- Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Amna Hafeez
- Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Yasmin Badshah
- Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Kanza Shahid
- Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Naeem Mahmood Ashraf
- School of Biochemistry & Biotechnology, University of the Punjab, Lahore, Pakistan
| | - Maria Shabbir
- Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
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A genetically-encoded crosslinker screen identifies SERBP1 as a PKCε substrate influencing translation and cell division. Nat Commun 2021; 12:6934. [PMID: 34836941 PMCID: PMC8626422 DOI: 10.1038/s41467-021-27189-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/08/2021] [Indexed: 01/09/2023] Open
Abstract
The PKCε-regulated genome protective pathway provides transformed cells a failsafe to successfully complete mitosis. Despite the necessary role for Aurora B in this programme, it is unclear whether its requirement is sufficient or if other PKCε cell cycle targets are involved. To address this, we developed a trapping strategy using UV-photocrosslinkable amino acids encoded in the PKCε kinase domain. The validation of the mRNA binding protein SERBP1 as a PKCε substrate revealed a series of mitotic events controlled by the catalytic form of PKCε. PKCε represses protein translation, altering SERBP1 binding to the 40 S ribosomal subunit and promoting the assembly of ribonucleoprotein granules containing SERBP1, termed M-bodies. Independent of Aurora B, SERBP1 is shown to be necessary for chromosome segregation and successful cell division, correlating with M-body formation. This requirement for SERBP1 demonstrates that Aurora B acts in concert with translational regulation in the PKCε-controlled pathway exerting genome protection.
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Co-ordinated control of the Aurora B abscission checkpoint by PKCε complex assembly, midbody recruitment and retention. Biochem J 2021; 478:2247-2263. [PMID: 34143863 PMCID: PMC8238520 DOI: 10.1042/bcj20210283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 11/17/2022]
Abstract
A requirement for PKCε in exiting from the Aurora B dependent abscission checkpoint is associated with events at the midbody, however, the recruitment, retention and action of PKCε in this compartment are poorly understood. Here, the prerequisite for 14-3-3 complex assembly in this pathway is directly linked to the phosphorylation of Aurora B S227 at the midbody. However, while essential for PKCε control of Aurora B, 14-3-3 association is shown to be unnecessary for the activity-dependent enrichment of PKCε at the midbody. This localisation is demonstrated to be an autonomous property of the inactive PKCε D532N mutant, consistent with activity-dependent dissociation. The C1A and C1B domains are necessary for this localisation, while the C2 domain and inter-C1 domain (IC1D) are necessary for retention at the midbody. Furthermore, it is shown that while the IC1D mutant retains 14-3-3 complex proficiency, it does not support Aurora B phosphorylation, nor rescues division failure observed with knockdown of endogenous PKCε. It is concluded that the concerted action of multiple independent events facilitates PKCε phosphorylation of Aurora B at the midbody to control exit from the abscission checkpoint.
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