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Ectodomain shedding of L1 adhesion molecule promotes cell migration by autocrine binding to integrins.

Mechtersheimer S, Gutwein P, Agmon-Levin N, Stoeck A, Oleszewski M, Riedle S, Postina R, Fahrenholz F, Fogel M, Lemmon V, Altevogt P - J. Cell Biol. (2001)

Bottom Line: The induction of migration was blocked by alpha v beta 5-specific antibodies and required Arg-Gly-Asp sites in L1.We propose that ectodomain-released L1 promotes migration by autocrine/paracrine stimulation via alpha v beta 5.This regulatory loop could be relevant for migratory processes under physiological and pathophysiological conditions.

View Article: PubMed Central - PubMed

Affiliation: Tumor Immunology Program, G0100, German Cancer Research Center, D-69120 Heidelberg, Germany.

ABSTRACT
The L1 adhesion molecule plays an important role in axon guidance and cell migration in the nervous system. L1 is also expressed by many human carcinomas. In addition to cell surface expression, the L1 ectodomain can be released by a metalloproteinase, but the biological function of this process is unknown. Here we demonstrate that membrane-proximal cleavage of L1 can be detected in tumors and in the developing mouse brain. The shedding of L1 involved a disintegrin and metalloproteinase (ADAM)10, as transfection with dominant-negative ADAM10 completely abolishes L1 release. L1-transfected CHO cells (L1-CHO) showed enhanced haptotactic migration on fibronectin and laminin, which was blocked by antibodies to alpha v beta 5 and L1. Migration of L1-CHO cells, but not the basal migration of CHO cells, was blocked by a metalloproteinase inhibitor, indicating a role for L1 shedding in the migration process. CHO and metalloproteinase-inhibited L1-CHO cells were stimulated to migrate by soluble L1-Fc protein. The induction of migration was blocked by alpha v beta 5-specific antibodies and required Arg-Gly-Asp sites in L1. A 150-kD L1 fragment released by plasmin could also stimulate CHO cell migration. We propose that ectodomain-released L1 promotes migration by autocrine/paracrine stimulation via alpha v beta 5. This regulatory loop could be relevant for migratory processes under physiological and pathophysiological conditions.

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Related in: MedlinePlus

L1-32 can be detected in the developing mouse brain. Mouse brains of different ages were homogenized in lysis buffer, and equal amounts of protein were analyzed by SDS-PAGE and Western blotting using pcytL1 followed by peroxidase-conjugated secondary antibodies and ECL detection.
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fig4: L1-32 can be detected in the developing mouse brain. Mouse brains of different ages were homogenized in lysis buffer, and equal amounts of protein were analyzed by SDS-PAGE and Western blotting using pcytL1 followed by peroxidase-conjugated secondary antibodies and ECL detection.

Mentions: L1 plays an important role in brain development. We examined the possibility that ectodomain cleavage of L1 occurred in vivo. Mouse brains of different ages were lysed, and equal amounts of protein were analyzed by Western blotting using pcytL1. To avoid post-lysis cleavage of L1, the lysates were prepared in the presence of 10 mM EDTA and 2 mM 1,10 phenanthroline, conditions that are known to block metalloproteinase activity. As shown in Fig. 4, L1-32 was most prominent in newborn P1 mice but declined at later stages. The low level of L1-220 and the absence of L1-85 in E15 brain is in agreement with earlier studies using rat brain (Liljelund et al., 1994). Densitometric analysis of band intensities revealed a L1-220/L1-32 ratio of approximately 4:1 in P1 brain that changed at later ages. This suggests that the level of L1-32 cleavage is highest in P1 brain, but the onset of cleavage probably occurred earlier. These data confirm and extend the results of Liljelund, showing that the expression of L1 and the proteolytic cleavage are developmentally regulated.


Ectodomain shedding of L1 adhesion molecule promotes cell migration by autocrine binding to integrins.

Mechtersheimer S, Gutwein P, Agmon-Levin N, Stoeck A, Oleszewski M, Riedle S, Postina R, Fahrenholz F, Fogel M, Lemmon V, Altevogt P - J. Cell Biol. (2001)

L1-32 can be detected in the developing mouse brain. Mouse brains of different ages were homogenized in lysis buffer, and equal amounts of protein were analyzed by SDS-PAGE and Western blotting using pcytL1 followed by peroxidase-conjugated secondary antibodies and ECL detection.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2198870&req=5

fig4: L1-32 can be detected in the developing mouse brain. Mouse brains of different ages were homogenized in lysis buffer, and equal amounts of protein were analyzed by SDS-PAGE and Western blotting using pcytL1 followed by peroxidase-conjugated secondary antibodies and ECL detection.
Mentions: L1 plays an important role in brain development. We examined the possibility that ectodomain cleavage of L1 occurred in vivo. Mouse brains of different ages were lysed, and equal amounts of protein were analyzed by Western blotting using pcytL1. To avoid post-lysis cleavage of L1, the lysates were prepared in the presence of 10 mM EDTA and 2 mM 1,10 phenanthroline, conditions that are known to block metalloproteinase activity. As shown in Fig. 4, L1-32 was most prominent in newborn P1 mice but declined at later stages. The low level of L1-220 and the absence of L1-85 in E15 brain is in agreement with earlier studies using rat brain (Liljelund et al., 1994). Densitometric analysis of band intensities revealed a L1-220/L1-32 ratio of approximately 4:1 in P1 brain that changed at later ages. This suggests that the level of L1-32 cleavage is highest in P1 brain, but the onset of cleavage probably occurred earlier. These data confirm and extend the results of Liljelund, showing that the expression of L1 and the proteolytic cleavage are developmentally regulated.

Bottom Line: The induction of migration was blocked by alpha v beta 5-specific antibodies and required Arg-Gly-Asp sites in L1.We propose that ectodomain-released L1 promotes migration by autocrine/paracrine stimulation via alpha v beta 5.This regulatory loop could be relevant for migratory processes under physiological and pathophysiological conditions.

View Article: PubMed Central - PubMed

Affiliation: Tumor Immunology Program, G0100, German Cancer Research Center, D-69120 Heidelberg, Germany.

ABSTRACT
The L1 adhesion molecule plays an important role in axon guidance and cell migration in the nervous system. L1 is also expressed by many human carcinomas. In addition to cell surface expression, the L1 ectodomain can be released by a metalloproteinase, but the biological function of this process is unknown. Here we demonstrate that membrane-proximal cleavage of L1 can be detected in tumors and in the developing mouse brain. The shedding of L1 involved a disintegrin and metalloproteinase (ADAM)10, as transfection with dominant-negative ADAM10 completely abolishes L1 release. L1-transfected CHO cells (L1-CHO) showed enhanced haptotactic migration on fibronectin and laminin, which was blocked by antibodies to alpha v beta 5 and L1. Migration of L1-CHO cells, but not the basal migration of CHO cells, was blocked by a metalloproteinase inhibitor, indicating a role for L1 shedding in the migration process. CHO and metalloproteinase-inhibited L1-CHO cells were stimulated to migrate by soluble L1-Fc protein. The induction of migration was blocked by alpha v beta 5-specific antibodies and required Arg-Gly-Asp sites in L1. A 150-kD L1 fragment released by plasmin could also stimulate CHO cell migration. We propose that ectodomain-released L1 promotes migration by autocrine/paracrine stimulation via alpha v beta 5. This regulatory loop could be relevant for migratory processes under physiological and pathophysiological conditions.

Show MeSH
Related in: MedlinePlus