Ubiquitination and endocytosis of cell adhesion molecule DM-GRASP regulate its cell surface presence and affect its role for axon navigation
DM-GRASP, cell adhesion molecule of the immunoglobulin superfamily, has been shown to promote growth and navigation of axons. We here demonstrate that clustering of DM-GRASP in the plasma membrane induces its rapid internalization via dynamin- and clathrin-dependent endocytosis, which is controlled...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
September 12, 2008
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| In: |
The journal of biological chemistry
Year: 2008, Volume: 283, Issue: 47, Pages: 32792-32801 |
| ISSN: | 1083-351X |
| DOI: | 10.1074/jbc.M805896200 |
| Online Access: | Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1074/jbc.M805896200 Verlag, kostenfrei, Volltext: http://www.jbc.org/content/283/47/32792 
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| Author Notes: | Karsten Thelen, Tanja Georg, Stefanie Bertuch, Pavol Zelina, and G. Elisabeth Pollerberg |
| Summary: | DM-GRASP, cell adhesion molecule of the immunoglobulin superfamily, has been shown to promote growth and navigation of axons. We here demonstrate that clustering of DM-GRASP in the plasma membrane induces its rapid internalization via dynamin- and clathrin-dependent endocytosis, which is controlled by phosphatidylinositol 3-kinase and mitogen-activated protein kinase ERK. The clustering of DM-GRASP activates ERK; the intensity and duration of ERK activation by DM-GRASP do not depend on rapid clathrin-mediated internalization of DM-GRASP. Moreover, the preference of retinal ganglion cell axons for DM-GRASP-coated micro-lanes requires clathrin-mediated endocytosis for the appropriate axonal turning reactions at substrate borders. Because the intracellular domain of DM-GRASP does not contain motifs for direct interactions with the endocytosis machinery, we performed a yeast two-hybrid screen to identify intracellular proteins mediating the uptake of DM-GRASP and isolated ubiquitin. Immunoprecipitation of DM-GRASP coexpressed with ubiquitin revealed that one or two ubiquitin(s) are attached to the intracellular domain of cell surface-resident DM-GRASP. Furthermore, elevated ubiquitination levels result in a decrease of cell surface-resident DM-GRASP as well as in the amount of total DM-GRASP. The endocytosis rate is not affected, but the delivery to multivesicular bodies is increased, indicating that DM-GRASP ubiquitination enhances its sorting into the degradation pathway. Together, our data show that ubiquitination and endocytosis of DM-GRASP in concert regulate its cell surface concentration, which is crucial for its function in axon navigation. |
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| Item Description: | Gesehen am 09.05.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1083-351X |
| DOI: | 10.1074/jbc.M805896200 |