Abstract
L1 is a neural cell adhesion molecule critical for neural development. Full-length L1 (L1FL) contains an alternatively spliced cytoplasmic sequence, RSLE, which is absent in L1 expressed in nonneuronal cells. The RSLE sequence follows a tyrosine, creating an endocytic motif that allows rapid internalization via clathrin-mediated endocytosis. We hypothesized that L1FL would internalize more rapidly than L1 lacking the RSLE sequence (L1ΔRSLE) and that internalization might regulate L1- mediated adhesion. L1 internalization was measured by immunofluorescence microscopy and by uptake of 125I-anti-rat-L1 antibody, demonstrating that L1FL is internalized 2-3 times faster than L1ΔRSLE. Inhibition of clathrin-mediated endocytosis slowed internalization of L1FL but did not affect initial uptake of L1ΔRSLE. To test whether L1 endocytosis regulates L1 adhesion, cell aggregation rates were tested. L1ΔRSLE cells aggregated two times faster than L1FL cells. Inhibition of clathrin-mediated endocytosis increases the aggregation rate of the L1FL cells to that of L1ΔRSLE cells. Our results demonstrate that rapid internalization of L1 dramatically affects L1 adhesion.
Original language | English (US) |
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Pages (from-to) | 1285-1290 |
Number of pages | 6 |
Journal | Journal of Biological Chemistry |
Volume | 276 |
Issue number | 2 |
DOIs | |
State | Published - Jan 12 2001 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology