Biochem Biophys Res Commun 2015 Oct 18;465(4):725-31. Epub 2015 Aug 18.

Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address:

SET domain, bifurcated 1 (SETDB1) is a histone methyltransferase that methylates lysine 9 on histone H3. Although it is important to know the localization of proteins to elucidate their physiological function, little is known of the subcellular localization of human SETDB1. In the present study, to investigate the subcellular localization of hSETDB1, we established a human cell line constitutively expressing enhanced green fluorescent protein fused to hSETDB1. We then generated a monoclonal antibody against the hSETDB1 protein. Expression of both exogenous and endogenous hSETDB1 was observed mainly in the cytoplasm of various human cell lines. Combined treatment with the nuclear export inhibitor leptomycin B and the proteasome inhibitor MG132 led to the accumulation of hSETDB1 in the nucleus. These findings suggest that hSETDB1, localized in the nucleus, might undergo degradation by the proteasome and be exported to the cytosol, resulting in its detection mainly in the cytosol.

J Biol Chem 2009 Feb 31;284(9):5753-62. Epub 2008 Dec 31.

Department of Pharmacology and Frontier Technology Center, Kyoto University Faculty of Medicine, Kyoto 606-8501, Japan.

Mammalian homolog of Drosophila diaphanous (mDia) consisting of three isoforms, mDia1, mDia2, and mDia3, is an effector of Rho GTPases that catalyzes actin nucleation and polymerization. Although the mDia actions on actin dynamics in the cytoplasm have been well studied, whether mDia accumulates and functions in the nucleus remains largely unknown. Given the presence of actin and actin-associated proteins in the nucleus, we have examined nuclear localization of mDia isoforms. Read More

PLoS One 2012 5;7(1):e29559. Epub 2012 Jan 5.

Department of Molecular Biology II, Faculty of Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Essen, Germany.

In higher eukaryotes, PAPS synthases are the only enzymes producing the essential sulphate-donor 3'-phospho-adenosine-5'-phosphosulphate (PAPS). Recently, PAPS synthases have been associated with several genetic diseases and retroviral infection. To improve our understanding of their pathobiological functions, we analysed the intracellular localisation of the two human PAPS synthases, PAPSS1 and PAPSS2. Read More

Gene 2007 Apr 8;391(1-2):26-38. Epub 2006 Dec 8.

Baylor College of Medicine, Department of Molecular and Human Genetics, Houston, TX 77030, USA.

Mutations in a human RecQ helicase homologue, RECQL4, have been identified in patients with Type II Rothmund-Thomson syndrome (RTS) with osteosarcoma predisposition, RAPADILINO syndrome, and Baller-Gerold syndrome. A role in DNA replication initiation has been demonstrated and mapped to the amino terminus upstream of the helicase domain; however, no nuclear localization signal (NLS) has been identified by sequence analysis. Here, we show both endogenous and green fluorescent protein (GFP)-tagged RECQL4 are nuclear and cytoplasmic in transformed cell lines. Read More

J Cell Biol 2011 Sep;194(5):689-703

p53/MDM2 Research Group, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3GA, England, UK.

The correlation between stress-induced nucleolar disruption and abrogation of p53 degradation is evident after a wide variety of cellular stresses. This link may be caused by steps in p53 regulation occurring in nucleoli, as suggested by some biochemical evidence. Alternatively, nucleolar disruption also causes redistribution of nucleolar proteins, potentially altering their interactions with p53 and/or MDM2. Read More