Characterization of a Novel Rat Brain Glycosylphosphatidylinositol-anchored Protein (Kilon), a Member of the IgLON Cell Adhesion Molecule Family

Abstract

In the central nervous system, many cell adhesion molecules are known to participate in the establishment and remodeling of the neural circuit. Some of the cell adhesion molecules are known to be anchored to the membrane by the glycosylphosphatidylinositol (GPI) inserted to their C termini, and many GPI-anchored proteins are known to be localized in a Triton-insoluble membrane fraction of low density or so-called "raft." In this study, we surveyed the GPI-anchored proteins in the Triton-insoluble low density fraction from 2-weekold rat brain by solubilization with phosphatidylinositol-specific phospholipase C. By Western blotting and partial peptide sequencing after the deglycosylation with peptide N-glycosidase F, the presence of Thy-1, F3/contactin, and T-cadherin was shown. In addition, one of the major proteins, having an apparent molecular mass of 36 kDa after the peptide N-glycosidase F digestion, was found to be a novel protein. The result of cDNA cloning showed that the protein is an immunoglobulin superfamily member with three C2 domains and has six putative glycosylation sites. Since this protein shows high sequence similarity to IgLON family members including LAMP, OBCAM, neurotrimin, CEPU-1, AvGP50, and GP55, we termed this protein Kilon (a kindred of IgLON). Kilon-specific monoclonal antibodies were produced, and Western blotting analysis showed that expression of Kilon is restricted to brain, and Kilon has an apparent molecular mass of 46 kDa in SDS-polyacrylamide gel electrophoresis in its expressed form. In brain, the expression of Kilon is already detected in E16 stage, and its level gradually increases during development. Kilon immunostaining was observed in the cerebral cortex and hippocampus, in which the strongly stained puncta were observed on dendrites and soma of pyramidal neurons.

Identification of chromosomal aberrations associated with disease progression and a novel 3q13.31 deletion involving LSAMP gene in osteosarcoma

“…Silencing LSAMP expression in human aortic smooth muscle cells (SMCs) substantially increased SMCs proliferation (52). LSAMP is a member of the IgLON immunoglobulin subfamily of glycosylphosphatidylinositol-anchored cell adhesion molecules comprised of LSAMP (53), opioid binding protein/cell adhesion moleculelike neurotrimin (OPCML) (54,55) and neuronal growth regulator 1 (NEGR1) (56). OPCML exhibits functional characteristics of a tumor suppressor gene in ovarian cancer in vitro and in vivo models and is underexpressed in 83% of sporadic ovarian cancers (57).…”

The Transcriptional Regulators TAZ and YAP Direct Transforming Growth Factor β-induced Tumorigenic Phenotypes in Breast Cancer Cells

“…The top two genes synergistically induced by TAZ/YAP⅐TEAD and TGF␤ identified in our analysis were NEGR1 and UCA1. NEGR1 encodes a cell adhesion molecule that plays a role in neuronal growth and development (53)(54)(55)(56)(57)(58)(59). UCA1 encodes a long noncoding RNA that is expressed in development, is turned off in homeostatic tissues, and has been found to be highly expressed in bladder carcinomas (60).…”

Genomic organization of a novel glycosylphosphatidylinositol MAM gene expressed in human tissues and tumors

“…Several of these proteins are involved in cell adhesion and subsequent cleavage of the anchor by a speci®c phospholipase or another hydrolase, would be a mechanism for terminating cellcell interaction (Funatsu et al, 1999). The immunoglobulin superfamily, the largest class of CAMs includes some well characterized GPI-anchored proteins, some of which are implicated in human cancers (Kim et al, 1992;Ilantzis et al, 1997;Peck and Walsh, 1993).…”