J Biol Chem, Vol. 274, Issue 38, 27249-27256, September 17, 1999
Amyloid Precursor-like Protein 2 Promotes Cell Migration
toward Fibronectin and Collagen IV
Xin-Fang
Li
,
Gopal
Thinakaran¶,
Sangram S.
Sisodia¶, and
Fu-Shin X.
Yu
From the
Schepens Eye Research Institute, Harvard
Medical School, Boston, Massachusetts 02114 and the ¶ Department
of Pharmacological and Physiological Sciences, University of Chicago,
Chicago, Illinois 60637
Previous studies have established that in
response to wounding, the expression of amyloid precursor-like protein
2 (APLP2) in the basal cells of migrating corneal epithelium is greatly up-regulated. To further our understanding of the functional
significance of APLP2 in wound healing, we have measured the migratory
response of transfected Chinese hamster ovary (CHO) cells expressing
APLP2 isoforms to a variety of extracellular matrix components
including laminin, collagen types I, IV, and VII, fibronectin, and
heparan sulfate proteoglycans (HSPGs). CHO cells overexpressing either of two APLP2 variants, differing in chondroitin sulfate (CS)
attachment, exhibit a marked increase in chemotaxis toward type IV
collagen and fibronectin but not to laminin, collagen types I and VII, and HSPGs. Cells overexpressing APLP2-751 (CS-modified) exhibited a
greater migratory response to fibronectin and type IV collagen than
their non-CS-attached counterparts (APLP2-763), suggesting that CS
modification enhanced APLP2 effects on cell migration. Moreover, in the
presence of chondroitin sulfate, transfectants overexpressing APLP2-751
failed to exhibit this enhanced migration toward fibronectin. The
APLP2-ECM interactions were also explored by solid phase adhesion
assays. While overexpression of APLP2 isoforms moderately enhanced CHO
adhesion to laminin, collagen types I and VII, and HSPGs lines,
especially those overexpressing APLP2-751, exhibited greatly increased
adhesion to type IV collagen and fibronectin. These observations
suggest that APLP2 contributes to re-epithelialization during wound
healing by supporting epithelial cell adhesion to fibronectin and
collagen IV, thus influencing their capacity to migrate over the wound
bed. Furthermore, APLP2 interactions with fibronectin and collagen IV
appear to be potentiated by the addition of a CS chain to the core proteins.
Copyright © 1999 by The American Society for Biochemistry and Molecular Biology, Inc.