# STRUCTURE AND ASSEMBLY OF INTERMEDIATE FILAMENTS

> **NIH NIH R01** · UNIVERSITY OF CINCINNATI · 1988 · $164,242

## Abstract

Intermediate filaments (IF), microfilaments, microtubules and
their accessory proteins make up the cytoskeleton, a complex
structure that plays a major role in the maintenance of cell form.
In this project, we will examine the structure and assembly
properties of the IF proteins in muscle and nerve cells using
chemical and high resolution morphological techniques.  We will
chemically synthesize a number of peptides whose amino acid
sequences are selected from the sequences of desmin and the
neurofilament (NF) triplet polypeptides and then use them to
examine the functional role of the protein domains from which
they are taken.  For desmin, we will use the peptides directly as
competitive inhibitors of filament assembly, as measured by a
new fluorescence assay that we have developed.  Concomitantly,
images of the arrested assembly products at molecular resolution
will be generated using the quick-freeze, deep-etch technique for
electron microscopy (EM).  By examining how the subunits are
prevented from fitting into the IF we hope to be able to
understand how the subunits are packed in a normal filament.
Polyclonal antisera will be generated against the NF-derived
synthetic peptides, which are taken from the C-terminal
extensions of the triplet, NF-L, NF-M and NF-H.  The antibodies
will be used in immunoblotting and immunolabeling experiments
to test the hypothesis that the C-terminal extensions make up the
NF crossbridges and to localize the putative phosphorylation site
of NF-M.  We will also determine, by fluorescence energy transfer
experiments, whether IF subunits are structurally polar or apolar,
and by two ultrastructural approaches if they assemble
unidirectionally or bidirectionally.  To explore the notion that IF
may be more dynamic than commonly though, we will look for
exchange of desmin subunits between formed filaments in vitro
and follow the fate of fluorescently labeled desmin subunits after
microinjection into developing cardiac and skeletal muscle cells.

Our long term goal is to map the roles played by the various
domains of the IF protein molecule in filament structure and
eventually to modify those of functional interest.  This may allow
us to insert modified IF protein molecules into the cytoskeleton as
a means to gain better understanding of cytoskeletal
morphogenesis.  Knowledge at this level may contribute to the
understanding of cardiac and skeletal muscle morphogenesis at
higher levels of organization and thus lead to more effective
prevention of heart and other muscle diseases.

## Key facts

- **NIH application ID:** 3157423
- **Project number:** 2R01AR035973-04A1
- **Recipient organization:** UNIVERSITY OF CINCINNATI
- **SAM.gov UEI:** DZ4YCZ3QSPR5
- **Principal Investigator:** WALLACE S IP
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $164,242
- **Award type:** 2
- **Project period:** 1985-01-01 → 1993-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3157423

## Citation

> US National Institutes of Health, RePORTER application 3157423, STRUCTURE AND ASSEMBLY OF INTERMEDIATE FILAMENTS (2R01AR035973-04A1). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3157423. Licensed CC0.

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