CELL RECOGNITION OF THE LONG ARM OF LAMININ

Project Details

Description

During embryonic development, regeneration and wound repair, members of the
basement membrane laminin family of structural glycoproteins provide
important signals for cell adhesion, shape, polarity, migration and
differentiation. The long arm of laminin is central to these processes,
affecting such functions as kidney tubule development, the migration and
differentiation of myoblasts, and the guidance of axonal and dendritic
processes to their targets. Some of the cell receptors involved in these
functions are highly specific for the long arm of laminin, or its variants,
while others are promiscuous in their recognition. For both there is
growing evidence that receptor recognition of the long arm is dependent on
the trimeric assembly of A, B1 and B2 chain subunits into conformationally-
correct rod and globular (G) domains. Furthermore, preliminary studies
reveal that specific biological activities can be reconstituted y the
intercalation of recombinant with authentic laminin chains.

A long term goal is to understand the molecular basis for laminin-cell
signaling in which tertiary and quaternary structure play a crucial role
and in which different isoform chain substitutions provide different
signals. This proposal is based upon an experimental approach which
combines genetic engineering, protein biochemistry, immunochemistry,
biophysics and cell biology. Recombinant glycoproteins, both normal and
containing a variety of sequence modification, will be generated with the
eukaryotic baculovirus expression system (with limited comparative studies
using mammalian recombinant molecules) and intercalated with authentic or
other recombinant chains. The refolded substrate structures will be
characterized by biophysical, biochemical and electron microscopy
techniques and function will be evaluated in cell interaction and receptor
binding studies with the aid of receptor- and substrate-specific
neutralizing and immunoprecipitating antibodies. In particular, the focus
will be on HT1080 fibrosarcoma cell and C2C12 myoblast adhesion and
spreading, PC12 pheochromocytoma cell neurite-outgrowth, olfactory
epithelial cell neurite-outgrowth and migration, and the binding
interactions of alpha7beta1 and alpha3beta1 integrins to these substrates.
The sites of recognition will be mapped and the role of conformation will
be determined with the experimental approach divided into an analysis of
the contributions of [1] the globular domain, [II] the rod domain, and
[III] variant chains of laminin to cell function.

Overall, these studies will lead to a better understanding of how basement
membranes in general, and laminin in particular, encode specific
information for interacting cells.
StatusFinished
Effective start/end date2/1/954/30/99

Funding

  • National Institute of Diabetes and Digestive and Kidney Diseases
  • National Institute of Diabetes and Digestive and Kidney Diseases
  • National Institute of Diabetes and Digestive and Kidney Diseases
  • National Institute of Diabetes and Digestive and Kidney Diseases

ASJC

  • Cell Biology

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