Interaction between an Integral Protein of the Nuclear Envelope Inner Membrane and Human Chromodomain Proteins Homologous to Drosophila HP1

doi:10.1074/jbc.271.25.14653

Interaction between an Integral Protein of the Nuclear Envelope Inner Membrane and Human Chromodomain Proteins Homologous to Drosophila HP1*

Qian Ye^‡ and
Howard J. Worman^§

From the Departments of Medicine and of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032

^§ Supported by American Cancer Society Grant CB-119 and a Silberberg Award from Columbia University. To whom correspondence should be addressed:
Dept. of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th St., 10th Floor, Rm. 508, New York, NY 10032.
Tel.: 212-305-8156; Fax: 212-305-6443; E-mail: worman{at}columbia.edu

Abstract

At the nuclear envelope in higher eukaryotic cells, the nuclear lamina and the heterochromatin are adjacent to the inner nuclear membrane, and their attachment is presumably mediated by integral membrane proteins. In a yeast two-hybrid screen, the nucleoplasmic domain of lamin B receptor (LBR), an integral protein of the inner nuclear membrane, associated with two human polypeptides homologous to Drosophila HP1, a heterochromatin protein involved in position-effect variegation. LBR fusion proteins bound to HP1 proteins synthesized by in vitro translation and present in cell lysates. Antibodies against LBR also co-immunoprecipitated HP1 proteins from cell extracts. LBR can interact with chromodomain proteins that are highly conserved in eukaryotic species and may function in the attachment of heterochromatin to the inner nuclear membrane in cells.

Footnotes

↵^‡ Supported in part by student research fellowships from the American Liver Foundation.
↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) U26311[GenBank] and U26312[GenBank].
↵¹ The abbreviations used are:

LBR

lamin B receptor

GST

glutathione-S-transferase

PAGE

polyacrylamide slab gel electrophoresis

PMSF

phenylmethylsulfonyl fluoride

BSA

bovine serum albumin.
- Received March 26, 1996.
- Revision received April 19, 1996.