Breaching the Diffusion Barrier That Compartmentalizes the Transmembrane Glycoprotein CE9 to the Posterior-Tail Plasma Membrane Domain of the Rat Spermatozoon

• Published in: The Journal of cell biology Vol. 120; no. 3; pp. 687 - 694
• Main Authors: Nehme, Cheryl L., Cesario, Mario M., Myles, Diana G., Koppel, Dennis E., Bartles, James R.
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01.02.1993; The Rockefeller University Press
• Subjects: Amino Acid Sequence; Amino acids; Animal reproduction; Animals; Antigens; Antigens, Surface; Base Sequence; Basigin; Biological and medical sciences; Blood Proteins - analysis; Blood Proteins - genetics; Blood Proteins - metabolism; Cell membranes; Complementary DNA; Diffusion; DNA - genetics; DNA - isolation & purification; Endothelial cells; Epithelial cells; Fluorescence; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Glycosylation; Kinetics; Male; Mammalian male genital system; Membrane Glycoproteins - analysis; Membrane Glycoproteins - genetics; Membrane Glycoproteins - metabolism; Membranes; Molecular Sequence Data; Morphology. Physiology; Plasma diffusion; Rats; Rats, Inbred F344; Rodents; Sperm Tail - metabolism; Sperm Tail - ultrastructure; Spermatozoa; Spermatozoa - metabolism; Spermatozoa - ultrastructure; Temperature; Time Factors; Vertebrates: reproduction; Cell compartment; Vertebrata; Epididymis; Mammalia; Rat; Rodentia; Plasma membrane; Glycoproteins; Diffusion; Localization; Testicle; Male genital system
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.120.3.687

CE9 is a posterior-tail domain-specific integral plasma membrane glycoprotein of the rat testicular spermatozoon. During epididymal maturation, CE9 undergoes endoproteolytic processing and then redistributes into the anterior-tail plasma membrane domain of the spermatozoon (Petruszak, J. A. M., C. L. Nehme, and J. R. Bartles. 1991. J. Cell. Biol. 114:917-927). We have determined the sequence of CE9 and found it to be a Type Ia transmembrane protein identical to the MRC OX-47 T-cell activation antigen, a member of the immunoglobulin superfamily predicted to have two immunoglobulin-related loops and three asparagine-linked glycans disposed extracellularly. Although encoded by a single gene and mRNA in the rat, the majority of spermatozoal CE9 is of smaller apparent molecular mass than its hepatocytic counterpart due to the under-utilization of sites for asparagine-linked glycosylation. By fluorescence recovery after photobleaching, CE9 was determined to be mobile within the posterior-tail plasma membrane domain of the living rat testicular spermatozoon, thus implying the existence of a regional barrier to lateral diffusion that is presumed to operate at the level of the annulus. Through the development of an in vitro system, the modification of this diffusion barrier to allow for the subsequent redistribution of CE9 into the anterior-tail domain was found to be a time-, temperature-, and energy-dependent process.