Cyclic AMP-dependent protein kinase phosphorylates merlin at serine 518 independently of p21-activated kinase and promotes merlin-ezrin heterodimerization

Kaija Alfthan, Leena Heiska, Mikaela Grönholm, G. Herma Renkema, Olli Carpen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Mutations in the NF2 tumor suppressor gene encoding merlin induce the development of tumors of the nervous system. Merlin is highly homologous to the ERM (ezrin-radixin-moesin) family of membrane/cytoskeleton linker proteins. However, the mechanism for the tumor suppressing activity of merlin is not well understood. Previously, we characterized a novel role for merlin as a protein kinase A (PKA)-anchoring protein, which links merlin to the cAMP/PKA signaling pathway. In this study we show that merlin is also a target for PKA-induced phosphorylation. In vitro [γ-33P]ATP labeling revealed that both the merlin N and C termini are phosphorylated by PKA. Furthermore, both in vitro and in vivo phosphorylation studies of the wild-type and mutated C termini demonstrated that PKA can phosphorylate merlin at serine 518, a site that is phosphorylated also by p21-activated kinases (PAKs). Merlin was phosphorylated by PKA in cells in which PAK activity was suppressed, indicating that the two kinases function independently. Both in vitro and in vivo interaction studies indicated that phosphorylation of serine 518 promotes heterodimerization between merlin and ezrin, an event suggested to convert merlin from a growth-suppressive to a growth-permissive state. This study provides further evidence on the connection between merlin and cAMP/PKA signaling and suggests a role for merlin in the cAMP/PKA transduction pathway.
Original languageEnglish
Pages (from-to)18559 - 18566
Number of pages8
JournalJournal of Biological Chemistry
Volume279
Issue number18
DOIs
Publication statusPublished - 2004
MoE publication typeA1 Journal article-refereed

Fingerprint

Neurofibromin 2
p21-Activated Kinases
Cyclic AMP-Dependent Protein Kinases
Serine
Phosphorylation
Tumors
ezrin
Nervous System Neoplasms
Gene encoding
Neurology
Growth
Tumor Suppressor Genes
Cytoskeleton

Keywords

  • tumor suppressor gene
  • merlin
  • phosphorylation

Cite this

Alfthan, Kaija ; Heiska, Leena ; Grönholm, Mikaela ; Renkema, G. Herma ; Carpen, Olli. / Cyclic AMP-dependent protein kinase phosphorylates merlin at serine 518 independently of p21-activated kinase and promotes merlin-ezrin heterodimerization. In: Journal of Biological Chemistry. 2004 ; Vol. 279, No. 18. pp. 18559 - 18566.
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abstract = "Mutations in the NF2 tumor suppressor gene encoding merlin induce the development of tumors of the nervous system. Merlin is highly homologous to the ERM (ezrin-radixin-moesin) family of membrane/cytoskeleton linker proteins. However, the mechanism for the tumor suppressing activity of merlin is not well understood. Previously, we characterized a novel role for merlin as a protein kinase A (PKA)-anchoring protein, which links merlin to the cAMP/PKA signaling pathway. In this study we show that merlin is also a target for PKA-induced phosphorylation. In vitro [γ-33P]ATP labeling revealed that both the merlin N and C termini are phosphorylated by PKA. Furthermore, both in vitro and in vivo phosphorylation studies of the wild-type and mutated C termini demonstrated that PKA can phosphorylate merlin at serine 518, a site that is phosphorylated also by p21-activated kinases (PAKs). Merlin was phosphorylated by PKA in cells in which PAK activity was suppressed, indicating that the two kinases function independently. Both in vitro and in vivo interaction studies indicated that phosphorylation of serine 518 promotes heterodimerization between merlin and ezrin, an event suggested to convert merlin from a growth-suppressive to a growth-permissive state. This study provides further evidence on the connection between merlin and cAMP/PKA signaling and suggests a role for merlin in the cAMP/PKA transduction pathway.",
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author = "Kaija Alfthan and Leena Heiska and Mikaela Gr{\"o}nholm and Renkema, {G. Herma} and Olli Carpen",
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Cyclic AMP-dependent protein kinase phosphorylates merlin at serine 518 independently of p21-activated kinase and promotes merlin-ezrin heterodimerization. / Alfthan, Kaija; Heiska, Leena; Grönholm, Mikaela; Renkema, G. Herma; Carpen, Olli (Corresponding Author).

In: Journal of Biological Chemistry, Vol. 279, No. 18, 2004, p. 18559 - 18566.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Cyclic AMP-dependent protein kinase phosphorylates merlin at serine 518 independently of p21-activated kinase and promotes merlin-ezrin heterodimerization

AU - Alfthan, Kaija

AU - Heiska, Leena

AU - Grönholm, Mikaela

AU - Renkema, G. Herma

AU - Carpen, Olli

PY - 2004

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N2 - Mutations in the NF2 tumor suppressor gene encoding merlin induce the development of tumors of the nervous system. Merlin is highly homologous to the ERM (ezrin-radixin-moesin) family of membrane/cytoskeleton linker proteins. However, the mechanism for the tumor suppressing activity of merlin is not well understood. Previously, we characterized a novel role for merlin as a protein kinase A (PKA)-anchoring protein, which links merlin to the cAMP/PKA signaling pathway. In this study we show that merlin is also a target for PKA-induced phosphorylation. In vitro [γ-33P]ATP labeling revealed that both the merlin N and C termini are phosphorylated by PKA. Furthermore, both in vitro and in vivo phosphorylation studies of the wild-type and mutated C termini demonstrated that PKA can phosphorylate merlin at serine 518, a site that is phosphorylated also by p21-activated kinases (PAKs). Merlin was phosphorylated by PKA in cells in which PAK activity was suppressed, indicating that the two kinases function independently. Both in vitro and in vivo interaction studies indicated that phosphorylation of serine 518 promotes heterodimerization between merlin and ezrin, an event suggested to convert merlin from a growth-suppressive to a growth-permissive state. This study provides further evidence on the connection between merlin and cAMP/PKA signaling and suggests a role for merlin in the cAMP/PKA transduction pathway.

AB - Mutations in the NF2 tumor suppressor gene encoding merlin induce the development of tumors of the nervous system. Merlin is highly homologous to the ERM (ezrin-radixin-moesin) family of membrane/cytoskeleton linker proteins. However, the mechanism for the tumor suppressing activity of merlin is not well understood. Previously, we characterized a novel role for merlin as a protein kinase A (PKA)-anchoring protein, which links merlin to the cAMP/PKA signaling pathway. In this study we show that merlin is also a target for PKA-induced phosphorylation. In vitro [γ-33P]ATP labeling revealed that both the merlin N and C termini are phosphorylated by PKA. Furthermore, both in vitro and in vivo phosphorylation studies of the wild-type and mutated C termini demonstrated that PKA can phosphorylate merlin at serine 518, a site that is phosphorylated also by p21-activated kinases (PAKs). Merlin was phosphorylated by PKA in cells in which PAK activity was suppressed, indicating that the two kinases function independently. Both in vitro and in vivo interaction studies indicated that phosphorylation of serine 518 promotes heterodimerization between merlin and ezrin, an event suggested to convert merlin from a growth-suppressive to a growth-permissive state. This study provides further evidence on the connection between merlin and cAMP/PKA signaling and suggests a role for merlin in the cAMP/PKA transduction pathway.

KW - tumor suppressor gene

KW - merlin

KW - phosphorylation

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DO - 10.1074/jbc.M313916200

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SP - 18559

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JO - Journal of Biological Chemistry

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SN - 0021-9258

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