Embigin, a developmentally expressed member of the immunoglobulin super family, is also expressed during regression of prostate and mammary gland

Abstract

Cell adhesion molecules (CAMs) are intimately involved in a variety of cellular processes, including development, cell growth, apoptosis, and differentiation. Interaction of CAMs with components of the extracellular matrix (ECM), growth factors, and other CAMs provides an intricate regulatory mechanism for a diverse range of cellular responses. Embigin is a developmentally expressed protein that is a member of the immunoglobulin superfamily (IgSF) class of CAMs. We have identified embigin as a gene expressed during tissue regression in rat prostate and lactating mammary gland following hormonal ablation. In the absence of the appropriate hormone, the secretory epithelial cells of these two tissues undergo successive waves of apoptotic cell death co‐incident with extensive reorganization of the surviving tissue. Using Northern analysis, in situ hybridization analysis, RT‐PCR, and Western analysis, we have characterized the expression of embigin mRNA and protein in both regressing prostate and mammary gland. During development of the prostate gland, increased expression of embigin is correlated with the appearance of highly organized lumenal and ductal structures. Embigin is also expressed in a variety of adult tissues including heart, liver, lung, and brain. Zoo‐blot analysis with the rat embigin cDNA indicates that embigin homologs exist in species as diverse as Homo sapiens and Drosophila melanogaster, suggesting that it has been highly conserved during evolution. Embigin protein is expressed at readily detectable levels in a variety of prostate and mammary cancer cell lines, and in some cell lines the expression of embigin appears to be down‐regulated in the presence of ECM. Our data have led us to propose a model in which embigin functions as a regulator of cell/ECM interactions during development and in the homeostasis of normal adult tissues. Dev. Genet. 21:268–278, 1997. © 1997 Wiley‐Liss, Inc.

Basigin (CD147) Is the Target for Organomercurial Inhibition of Monocarboxylate Transporter Isoforms 1 and 4

“…An obvious candidate for this would be gp70 (embigin), a close homologue of CD147 (17). gp70 is less widely expressed than CD147, and thus is not the normal binding partner for MCT1 and MCT4 (15), although it does associate with MCT1 in rat erythrocytes where the two proteins can be cross-linked by DIDS (14).…”

“…We demonstrate that pCMBS inhibits MCT1 and MCT4 activity by attacking a reactive disulfide bond in the Ig-like C2 domain of CD147 and disrupting its interaction with MCT1 or MCT4. We also identify the ancillary protein with which MCT2 interacts as embigin (gp70), a CD147 homologue with an un-reactive Ig-like V domain in place of the C2 domain (17). This provides an explanation for the insensitivity of MCT2 toward inhibition by pCMBS.…”

Molecular Features, Regulation, and Function of Monocarboxylate Transporters: Implications for Drug Delivery

“…3). 84–87 In brain, neuroplastin‐65 is associated with the post‐synaptic density,88 where, intriguingly, MCT2 is also localized 89. Therefore, an attractive idea is that other members of this family of CD147‐related glycoproteins may interact with some MCTs in a tissue‐specific manner to control MCT expression, trafficking, and transport activity.…”

Postnatal Ontogeny of Expression of Monocarboxylate Transporters(MCTs) and Two Regulatory Proteins, Basigin and Embigin, in The Epididymis of Male Rat

“…It is noteworthy for a drastic increase of embigin mRNA as aged. Embigin, a glycoprotein belonging to the immunoglobulin superfamily, functions as a regulator of cell/extracellular matrix (ECM) interactions during development and in the homeostasis of normal adult tissues (Guenette et al, 1998). Thus, it is supposed that embigin would play a role in tissue remodeling and/or in segmental differentiation of the epididymis during postnatal development.…”