title: The Effector Domain of MARCKS Is a Nuclear Localization Signal that Regulates Cellular PIP2 Levels and Nuclear PIP2 Localization.
abstract: Translocation to the nucleus of diacylglycerol kinase (DGK)- ζ is dependent on a sequence homologous to the effector domain of Myristoylated Alanine Rich C-Kinase Substrate (MARCKS). These data would suggest that MARCKS could also localize to the nucleus. A single report demonstrated immunofluorescence staining of MARCKS in the nucleus; however, further experimental evidence confirming the specific domain responsible for this localization has not been reported. Here, we report that MARCKS is present in the nucleus in GBM cell lines. We then over-expressed wild-type MARCKS (WT) and MARCKS with the effector domain deleted (ΔED), both tagged with V5-epitope in a GBM cell line with low endogenous MARCKS expression (U87). We found that MARCKS-WT localized to the nucleus, while the MARCKS construct without the effector domain remained in the cytoplasm. We also found that over-expression of MARCKS-WT resulted in a significant increase in total cellular phosphatidyl-inositol (4,5) bisphosphate (PIP2) levels, consistent with prior evidence that MARCKS can regulate PIP2 levels. We also found increased staining for PIP2 in the nucleus with MARCKS-WT over-expression compared to MARCKS ΔED by immunofluorescence. Interestingly, we observed MARCKS and PIP2 co-localization in the nucleus. Lastly, we found changes in gene expression when MARCKS was not present in the nucleus (MARCKS ΔED). These data indicate that the MARCKS effector domain can function as a nuclear localization signal and that this sequence is critical for the ability of MARCKS to regulate PIP2 levels, nuclear localization, and gene expression. These data suggests a novel role for MARCKS in regulating nuclear functions such as gene expression.
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Rohrbach
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Nishi
authors.initials: N
authors.lastname: Shah
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: William P
authors.initials: WP
authors.lastname: Jackson
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Erin V
authors.initials: EV
authors.lastname: Feeney
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Samantha
authors.initials: S
authors.lastname: Scanlon
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Gish
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Ryan
authors.initials: R
authors.lastname: Khodadadi
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Stephen O
authors.initials: SO
authors.lastname: Hyde
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Patricia H
authors.initials: PH
authors.lastname: Hicks
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Anderson
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: John S
authors.initials: JS
authors.lastname: Jarboe
authors.affiliation: The Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Willey
mesh_terms: D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D001692:Biological Transport; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002467:Cell Nucleus / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D057809:HEK293 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D019913:Nuclear Localization Signals / Q000737:chemistry / Q000502:physiology*; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D014407:Tumor Cells, Cultured
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C000619710:MARCKS protein, human; D008565:Membrane Proteins; D019913:Nuclear Localization Signals; D019269:Phosphatidylinositol 4,5-Diphosphate; D000076250:Myristoylated Alanine-Rich C Kinase Substrate