A Novel Ligand for CD44 Is Serglycin, a Hematopoietic Cell Lineage-specific Proteoglycan

doi:10.1074/jbc.270.13.7437

A Novel Ligand for CD44 Is Serglycin, a Hematopoietic Cell Lineage-specific Proteoglycan

POSSIBLE INVOLVEMENT IN LYMPHOID CELL ADHERENCE AND ACTIVATION (*)

From the (1)Department of Immunology, The Tokyo Metropolitan Institute of Medical Science, the
(2)Laboratory of Molecular Structure and Functions, Department of Molecular Biology, Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113, Japan and the
(3)Department of Immunology, Juntendo University, School of Medicine, and
(4)Department of Bioregulation, Biomedical Research Center, Osaka University Medical School, Osaka 565, Japan

^§ To whom correspondence should be addressed:
Dept. of Immunology, The Tokyo Metropolitan Institute of Medical Science, 3-18-22, Hon-Komagome, Bunkyo-Ku, Tokyo, Japan
. Tel.: 81-3-3823-2101 (ext. 5311); Fax: 81-3-5685-6608.

Abstract

The lymphocyte adhesion molecule CD44 recognizes a non-hyaluronate proteoglycan, gp600, secreted by mouse T cell line CTLL2. We now demonstrate that gp600 is identical to serglycin, a member of the small proteoglycan family stored in intracellular secretory granules of lymphoid, myeloid, and some tumor cells. Purified gp600 has the ability to bind specifically to CD44, and the binding is dependent on activation of CD44. The CD44-binding elements on gp600 or serglycin are glycosaminoglycans consisting of chondroitin 4-sulfate. Serglycin is readily exocytosed, and its interaction with active form CD44 augments the CD3-dependent degranulation of CD44 positive CTL clones. We conclude that the serglycin secreted from secretory granules of hematopoietic cells is a novel ligand for CD44, and could regulate lymphoid cell adherence and activation.

Footnotes

↵* This work was supported by a grant from the Science and Technology Agency and Grant-in-aid for Scientific Research on Priority Areas 06267225 from the Ministry of Education, Science and Culture, Japan. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

CHAPS

3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid

ELISA

enzyme-linked immunosorbent assay

BSA

bovine serum albumin

PBS

phosphate-buffered saline

HPLC

high performance liquid chromatography

CTL

cytotoxic T cell

BCECF

2′,7′-bis(2-carboxyethyl)-5(and −6)-carboxyfluorescein.
↵² N. Toyama-Sorimachi, unpublished observation.
↵³ N. Toyama-Sorimachi, unpublished observation.
- Received December 19, 1994.