Tissue distribution of liver regulating protein. Evidence for a cell recognition signal common to liver, pancreas, gonads, and hemopoietic tissues

• Published in: The American journal of pathology Vol. 145; no. 3; pp. 715 - 727
• Main Authors: Corlu, A, Ilyin, GP, Gerard, N, Kneip, B, Rissel, M, Jegou, B, Guguen-Guillouzo, C
• Format: Journal Article
• Language: English
• Published: Bethesda, MD ASIP 01.09.1994; American Society for Investigative Pathology; American Society for Investigative Pathology / Elsevier
• Subjects: Animals; Antibodies, Monoclonal; Biological and medical sciences; Cell interactions, adhesion; Female; Fundamental and applied biological sciences. Psychology; Germ Cells - chemistry; Hematopoietic System - chemistry; Life Sciences; Liver - chemistry; Liver - cytology; Male; Membrane Proteins - analysis; Membrane Proteins - chemistry; Microscopy, Electron; Molecular and cellular biology; Other; Pancreas - chemistry; Rats; Rats, Sprague-Dawley; Rat; Rodentia; Cell adhesion molecule; Cell cell interaction; Monoclonal antibody; Tissue; Vertebrata; Mammalia; Hepatocyte; Animal; Distribution; Plasma membrane; Immunofluorescence
• ISSN: 0002-9440; 1525-2191

Liver regulating protein (LRP) is an integral plasma membrane protein that plays a critical role in maintaining the differentiated phenotype of adult rat hepatocytes by mediating cell-cell interactions with rat liver epithelial cells. Using a specific monoclonal antibody (MAb L8) capable of inhibiting the interactions between these two cell types, the cellular distribution of LRP was analyzed in the liver. Various cell types, including hepatocytes and several sinusoidal cells, were found to be positive, whereas vascular endothelial cells and bile duct cells were consistently negative. This observation led us to question whether cells of nonhepatic origin would also express LRP. We show that MAb L8 immunoreactive material was detected in only three groups of tissues and corresponded to molecules similar to LRP but with different molecular weights. LRP-like molecules were demonstrated on acinar cells of the exocrine pancreas and on all hemopoietic cells regardless of their localization in the organism. LRP-like molecules were also expressed by germ cells and surrounding feeder cells in the testis and ovary in a stage-dependent manner. These results demonstrate the existence of a family of LRP proteins and strongly suggest a critical role for these molecules in regulating cell-cell communication in specific tissues.