title: Testis-specific cell adhesion molecule, CEACAM6-L, forms homophilic interaction at the cell adhesion site in vitro.
abstract: Ceacam6-L (carcinoembryonic antigen-related cell adhesion molecule 6-long) has recently been isolated from rat testis by differential display technique followed by RT-PCR and DNA sequence analysis. CEACAM6-L is a member of the immunoglobulin (Ig) superfamily and composed of an Ig-like domain, three IgCAM domains, a transmembrane region, and a short intracellular domain. We previously reported that CEACAM6-L was localized at the interface between Sertoli cells and elongating/elongated spermatids and might be an adhesion molecule contributing to apical ectoplasmic specialization in testis. In this study, we investigate the adhesive capacities and the complex structures of CEACAM6-L, using COS-7 cells as a study model. Transfection and immunoprecipitation experiments showed that CEACAM6-L expressed in the cells was distributed to the plasma membrane and interacted homophilically between transfected COS-7 cells. A chemical cross-linking experiment and a binding assay with recombinant CEACAM6-L proteins suggested that CEACAM6-L could form trans-tetra complexes, constructed by cis-homodimers at the adhesion site between COS-7 cells expressing CEACAM6-L. We hypothesized that CEACAM6-L expressed in both germ cells and Sertoli cells forms homophilic trans-tetra complexes between these cells in the seminiferous epithelium.
authors.affiliation: Graduate School of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kurio
authors.forename: Jae Man
authors.initials: JM
authors.lastname: Lee
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kusakabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iida
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D019556:COS Cells; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D005786:Gene Expression Regulation / Q000502:physiology; D008297:Male; D011485:Protein Binding; D051381:Rats; D011994:Recombinant Proteins; D013737:Testis / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C570771:CEACAM6 protein, rat; D015815:Cell Adhesion Molecules; D011994:Recombinant Proteins