NCAM is ubiquitylated, endocytosed and recycled in neurons.
The neural cell adhesion molecule NCAM plays an important role during neural development and in the adult brain. To study the intracellular trafficking of NCAM in neurons, two major isoforms, NCAM140 or NCAM180, were expressed in primary cortical neurons and in the rat B35 neuroblastoma cell line. NCAM was endocytosed and subsequently recycled to the plasma membrane, whereas only a minor fraction was degraded in lysosomes. In cortical neurons, endocytosis of NCAM was detected in the soma, neurites and growth cones in a developmentally regulated fashion. Furthermore, we found that NCAM is mono-ubiquitylated at the plasma membrane and endocytosis was significantly increased in cells overexpressing ubiquitin. Therefore, we propose that ubiquitylation represents an endocytosis signal for NCAM.
Diestel
Simone
S
Institute of Animal Sciences, Department of Biochemistry, University of Bonn, Katzenburgweg 9a, 53115 Bonn, Germany.
Schaefer
Daniel
D
Cremer
Harold
H
Schmitz
Brigitte
B
D000818:Animals; D021941:Caveolae / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002966:Clathrin / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D020439:Growth Cones / Q000378:metabolism; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D019006:Neural Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D021381:Protein Transport; D054875:Ubiquitination; D020695:rab4 GTP-Binding Proteins / Q000378:metabolism
D002966:Clathrin; D019006:Neural Cell Adhesion Molecules; D020695:rab4 GTP-Binding Proteins