Functional impact of Aurora A-mediated phosphorylation of HP1γ at serine 83 during cell cycle progression

Adrienne Grzenda; Phoebe Leonard; Seungmae Seo; Angela J. Mathison; Guillermo Urrutia; Ezequiel Calvo; Juan Iovanna; Raul Urrutia; Gwen Lomberk

doi:10.1186/1756-8935-6-21

Functional impact of Aurora A-mediated phosphorylation of HP1γ at serine 83 during cell cycle progression

Adrienne Grzenda, Phoebe Leonard, Seungmae Seo, Angela J. Mathison, Guillermo Urrutia, Ezequiel Calvo, Juan Iovanna, Raul Urrutia, Gwen Lomberk

Obstetrics, Gynecology and Women's Health - Reproductive Endocrinology and Infertility

Research output: Contribution to journal › Article › peer-review

18 Scopus citations

Abstract

Background: Previous elegant studies performed in the fission yeast Schizosaccharomyces pombe have identified a requirement for heterochromatin protein 1 (HP1) for spindle pole formation and appropriate cell division. In mammalian cells, HP1γ has been implicated in both somatic and germ cell proliferation. High levels of HP1γ protein associate with enhanced cell proliferation and oncogenesis, while its genetic inactivation results in meiotic and mitotic failure. However, the regulation of HP1γ by kinases, critical for supporting mitotic progression, remains to be fully characterized. Results: We report for the first time that during mitotic cell division, HP1γ colocalizes and is phosphorylated at serine 83 (Ser⁸³) in G ₂/M phase by Aurora A. Since Aurora A regulates both cell proliferation and mitotic aberrations, we evaluated the role of HP1γ in the regulation of these phenomena using siRNA-mediated knockdown, as well as phosphomimetic and nonphosphorylatable site-directed mutants. We found that genetic downregulation of HP1γ, which decreases the levels of phosphorylation of HP1γ at Ser⁸³ (P-Ser⁸³- HP1γ), results in mitotic aberrations that can be rescued by reintroducing wild type HP1γ, but not the nonphosphorylatable S83A-HP1γ mutant. In addition, proliferation assays showed that the phosphomimetic S83D-HP1γ increases 5-ethynyl-2́-deoxyuridine (EdU) incorporation, whereas the nonphosphorylatable S83A-HP1γ mutant abrogates this effect. Genome-wide expression profiling revealed that the effects of these mutants on mitotic functions are congruently reflected in G₂/M gene expression networks in a manner that mimics the on and off states for P-Ser⁸³-HP1γ. Conclusions: This is the first description of a mitotic Aurora A-HP1γ pathway, whose integrity is necessary for the execution of proper somatic cell division, providing insight into specific types of posttranslational modifications that associate to distinct functional outcomes of this important chromatin protein.

Original language	English (US)
Article number	21
Journal	Epigenetics and Chromatin
Volume	6
Issue number	1
DOIs	https://doi.org/10.1186/1756-8935-6-21
State	Published - 2013

Bibliographical note

Funding Information:
This work was supported by funding from the Fraternal Order of Eagles and a Career Development Award from the Mayo Clinic SPORE in Pancreatic Cancer (P50 CA102701, both to GL), as well as the National Institutes of Health (grant DK52913 to RU and T32CA148073 to AG), the Mayo Clinic Center for Cell Signaling in Gastroenterology (P30DK084567), and the Mayo Foundation. The authors would like to sincerely thank Dr Debora Bensi for technical assistance during the early development of this work, as well as Holger Dormann and Dr C David Allis for their generous contributions and helpful insights for the hesperidin P-Ser83-HP1γ experiments.

Keywords

Aurora kinase
Centrosome
Epigenetics
Heterochromatin protein 1 (HP1)
Mitosis
Spindle pole

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title = "Functional impact of Aurora A-mediated phosphorylation of HP1γ at serine 83 during cell cycle progression",

abstract = "Background: Previous elegant studies performed in the fission yeast Schizosaccharomyces pombe have identified a requirement for heterochromatin protein 1 (HP1) for spindle pole formation and appropriate cell division. In mammalian cells, HP1γ has been implicated in both somatic and germ cell proliferation. High levels of HP1γ protein associate with enhanced cell proliferation and oncogenesis, while its genetic inactivation results in meiotic and mitotic failure. However, the regulation of HP1γ by kinases, critical for supporting mitotic progression, remains to be fully characterized. Results: We report for the first time that during mitotic cell division, HP1γ colocalizes and is phosphorylated at serine 83 (Ser83) in G 2/M phase by Aurora A. Since Aurora A regulates both cell proliferation and mitotic aberrations, we evaluated the role of HP1γ in the regulation of these phenomena using siRNA-mediated knockdown, as well as phosphomimetic and nonphosphorylatable site-directed mutants. We found that genetic downregulation of HP1γ, which decreases the levels of phosphorylation of HP1γ at Ser83 (P-Ser83- HP1γ), results in mitotic aberrations that can be rescued by reintroducing wild type HP1γ, but not the nonphosphorylatable S83A-HP1γ mutant. In addition, proliferation assays showed that the phosphomimetic S83D-HP1γ increases 5-ethynyl-{\'2}-deoxyuridine (EdU) incorporation, whereas the nonphosphorylatable S83A-HP1γ mutant abrogates this effect. Genome-wide expression profiling revealed that the effects of these mutants on mitotic functions are congruently reflected in G2/M gene expression networks in a manner that mimics the on and off states for P-Ser83-HP1γ. Conclusions: This is the first description of a mitotic Aurora A-HP1γ pathway, whose integrity is necessary for the execution of proper somatic cell division, providing insight into specific types of posttranslational modifications that associate to distinct functional outcomes of this important chromatin protein.",

keywords = "Aurora kinase, Centrosome, Epigenetics, Heterochromatin protein 1 (HP1), Mitosis, Spindle pole",

author = "Adrienne Grzenda and Phoebe Leonard and Seungmae Seo and Mathison, {Angela J.} and Guillermo Urrutia and Ezequiel Calvo and Juan Iovanna and Raul Urrutia and Gwen Lomberk",

note = "Funding Information: This work was supported by funding from the Fraternal Order of Eagles and a Career Development Award from the Mayo Clinic SPORE in Pancreatic Cancer (P50 CA102701, both to GL), as well as the National Institutes of Health (grant DK52913 to RU and T32CA148073 to AG), the Mayo Clinic Center for Cell Signaling in Gastroenterology (P30DK084567), and the Mayo Foundation. The authors would like to sincerely thank Dr Debora Bensi for technical assistance during the early development of this work, as well as Holger Dormann and Dr C David Allis for their generous contributions and helpful insights for the hesperidin P-Ser83-HP1γ experiments.",

year = "2013",

doi = "10.1186/1756-8935-6-21",

language = "English (US)",

volume = "6",

journal = "Epigenetics and Chromatin",

issn = "1756-8935",

publisher = "BioMed Central Ltd.",

number = "1",

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TY - JOUR

T1 - Functional impact of Aurora A-mediated phosphorylation of HP1γ at serine 83 during cell cycle progression

AU - Grzenda, Adrienne

AU - Leonard, Phoebe

AU - Seo, Seungmae

AU - Mathison, Angela J.

AU - Urrutia, Guillermo

AU - Calvo, Ezequiel

AU - Iovanna, Juan

AU - Urrutia, Raul

AU - Lomberk, Gwen

N1 - Funding Information: This work was supported by funding from the Fraternal Order of Eagles and a Career Development Award from the Mayo Clinic SPORE in Pancreatic Cancer (P50 CA102701, both to GL), as well as the National Institutes of Health (grant DK52913 to RU and T32CA148073 to AG), the Mayo Clinic Center for Cell Signaling in Gastroenterology (P30DK084567), and the Mayo Foundation. The authors would like to sincerely thank Dr Debora Bensi for technical assistance during the early development of this work, as well as Holger Dormann and Dr C David Allis for their generous contributions and helpful insights for the hesperidin P-Ser83-HP1γ experiments.

PY - 2013

Y1 - 2013

N2 - Background: Previous elegant studies performed in the fission yeast Schizosaccharomyces pombe have identified a requirement for heterochromatin protein 1 (HP1) for spindle pole formation and appropriate cell division. In mammalian cells, HP1γ has been implicated in both somatic and germ cell proliferation. High levels of HP1γ protein associate with enhanced cell proliferation and oncogenesis, while its genetic inactivation results in meiotic and mitotic failure. However, the regulation of HP1γ by kinases, critical for supporting mitotic progression, remains to be fully characterized. Results: We report for the first time that during mitotic cell division, HP1γ colocalizes and is phosphorylated at serine 83 (Ser83) in G 2/M phase by Aurora A. Since Aurora A regulates both cell proliferation and mitotic aberrations, we evaluated the role of HP1γ in the regulation of these phenomena using siRNA-mediated knockdown, as well as phosphomimetic and nonphosphorylatable site-directed mutants. We found that genetic downregulation of HP1γ, which decreases the levels of phosphorylation of HP1γ at Ser83 (P-Ser83- HP1γ), results in mitotic aberrations that can be rescued by reintroducing wild type HP1γ, but not the nonphosphorylatable S83A-HP1γ mutant. In addition, proliferation assays showed that the phosphomimetic S83D-HP1γ increases 5-ethynyl-2́-deoxyuridine (EdU) incorporation, whereas the nonphosphorylatable S83A-HP1γ mutant abrogates this effect. Genome-wide expression profiling revealed that the effects of these mutants on mitotic functions are congruently reflected in G2/M gene expression networks in a manner that mimics the on and off states for P-Ser83-HP1γ. Conclusions: This is the first description of a mitotic Aurora A-HP1γ pathway, whose integrity is necessary for the execution of proper somatic cell division, providing insight into specific types of posttranslational modifications that associate to distinct functional outcomes of this important chromatin protein.

AB - Background: Previous elegant studies performed in the fission yeast Schizosaccharomyces pombe have identified a requirement for heterochromatin protein 1 (HP1) for spindle pole formation and appropriate cell division. In mammalian cells, HP1γ has been implicated in both somatic and germ cell proliferation. High levels of HP1γ protein associate with enhanced cell proliferation and oncogenesis, while its genetic inactivation results in meiotic and mitotic failure. However, the regulation of HP1γ by kinases, critical for supporting mitotic progression, remains to be fully characterized. Results: We report for the first time that during mitotic cell division, HP1γ colocalizes and is phosphorylated at serine 83 (Ser83) in G 2/M phase by Aurora A. Since Aurora A regulates both cell proliferation and mitotic aberrations, we evaluated the role of HP1γ in the regulation of these phenomena using siRNA-mediated knockdown, as well as phosphomimetic and nonphosphorylatable site-directed mutants. We found that genetic downregulation of HP1γ, which decreases the levels of phosphorylation of HP1γ at Ser83 (P-Ser83- HP1γ), results in mitotic aberrations that can be rescued by reintroducing wild type HP1γ, but not the nonphosphorylatable S83A-HP1γ mutant. In addition, proliferation assays showed that the phosphomimetic S83D-HP1γ increases 5-ethynyl-2́-deoxyuridine (EdU) incorporation, whereas the nonphosphorylatable S83A-HP1γ mutant abrogates this effect. Genome-wide expression profiling revealed that the effects of these mutants on mitotic functions are congruently reflected in G2/M gene expression networks in a manner that mimics the on and off states for P-Ser83-HP1γ. Conclusions: This is the first description of a mitotic Aurora A-HP1γ pathway, whose integrity is necessary for the execution of proper somatic cell division, providing insight into specific types of posttranslational modifications that associate to distinct functional outcomes of this important chromatin protein.

KW - Aurora kinase

KW - Centrosome

KW - Epigenetics

KW - Heterochromatin protein 1 (HP1)

KW - Mitosis

KW - Spindle pole

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DO - 10.1186/1756-8935-6-21

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C2 - 23829974

AN - SCOPUS:84879835428

SN - 1756-8935

VL - 6

JO - Epigenetics and Chromatin

JF - Epigenetics and Chromatin

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ER -

Functional impact of Aurora A-mediated phosphorylation of HP1γ at serine 83 during cell cycle progression

Abstract

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