Identification and characterization of CEPU-Se-A secreted isoform of the IgLON family protein, CEPU-1.
CEPU-1/Neurotrimin is a neuronal glycoprotein thought to play a role in axon guidance and cell-cell recognition. It is a member of the IgLON family, has three C2 domains, and is attached to the plasma membrane by a GPI-anchor. We report here the characterisation of an alternatively-spliced isoform of CEPU-1 that is secreted. This isoform, termed CEPU-Se, is coexpressed with CEPU-1 in retina, cerebellum, and DRG neurons. In the cerebellum CEPU-1/CEPU-Se is expressed predominantly on granule cells and in the molecular layer. Divalent but not monovalent CEPU-Se interacts with CEPU-1 and other IgLONs, suggesting that the ability of CEPU-Se to modify the activity of the IgLON family may require an additional cofactor. CEPU-Se does not support the outgrowth of DRG neurons or the extension of established growth cones; however, neurite outgrowth on laminin is unaffected by CEPU-Se. Our data suggest that CEPU-Se may act to modulate the ability of CEPU-1, LAMP, and OBCAM to influence neurite outgrowth.
Lodge
A P
AP
Department of Human Anatomy and Cell Biology, The University of Liverpool, New Medical School, Ashton Street, Liverpool L69 3GE, United Kingdom.
McNamee
C J
CJ
Howard
M R
MR
Reed
J E
JE
Moss
D J
DJ
D017398:Alternative Splicing / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D001483:Base Sequence; D016466:CHO Cells; D002455:Cell Division / Q000502:physiology; D002531:Cerebellum / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D002642:Chick Embryo; D006224:Cricetinae; D019281:Dimerization; D005727:Ganglia, Spinal / Q000166:cytology; D007136:Immunoglobulins / Q000737:chemistry / Q000235:genetics*; D007536:Isomerism; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016501:Neurites / Q000502:physiology; D009475:Neurons, Afferent / Q000166:cytology; D011485:Protein Binding / Q000502:physiology; D011689:Purkinje Cells / Q000737:chemistry / Q000502:physiology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D030161:Avian Proteins; D007136:Immunoglobulins; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; C102493:neural CEPU-1 protein, chicken