In:
Journal of Cell Science, The Company of Biologists, Vol. 108, No. 3 ( 1995-03-01), p. 907-915
Abstract:
A truncated form of fibronectin consisting of the N-terminal 70 kDa and C-terminal 37 kDa regions, desig-nated r70F2, retained the ability to assemble into the extra-cellular matrix when expressed in cultured fibroblasts (Ichihara-Tanaka et al. (1992)FEBS Lett. 299, 155-158). To elucidate the role of the C-terminal 37 kDa region in fibronectin matrix assembly, we expressed a panel of mutant forms of r70F2 with various deletions and amino acid substitutions in mouse L cells. Although substitution of Ser for two Cys residues in the C-terminal dimer-forming segment led to a marked reduction in the matrix assembly activity of r70F2, the resulting monomeric r70F2 still retained a low, but significant activity to assemble into the matrix. Neither the N-terminal 70 kDa nor the C-terminal 37 kDa regions, when expressed as monomeric forms, exhibited any residual activity, suggesting that the core domain of the 37 kDa region consisting of III15 and I10 through I12 modules, termed Fib2 domain, is actively involved in the matrix assembly of r70F2. In support of the role of Fib2 domain, the proteolytic fragment derived from the 37 kDa region inhibited the assembly of r70F2. Fur-thermore, en bloc deletion of the Fib2 domain or deletion of the I10 through I12 modules from r70F2 resulted in a marked decrease of the matrix assembly activity. Since deletion of any one of the three type I modules led to a much lesser decrease in activity, it seems likely that a cluster of the three type I modules in the Fib2 domain, but not any one in particular, serves as a functional unit for the matrix assembly of r70F2. Further supporting the active role of the Fib2 domain, a recombinant homodimer of the 37 kDa region was found to be incorporated into the deoxy-cholate-insoluble matrix. These results, taken together, indicate that the Fib2 domain per se has an intrinsic ability to assemble into the matrix and is actively involved in the matrix assembly of fibronectin.
Type of Medium:
Online Resource
ISSN:
0021-9533
,
1477-9137
DOI:
10.1242/jcs.108.3.907
Language:
English
Publisher:
The Company of Biologists
Publication Date:
1995
detail.hit.zdb_id:
219171-4
detail.hit.zdb_id:
1483099-1
SSG:
12
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