# MARKERS OF EPIDERMAL DIFFERENTIATION

> **NIH NIH R01** · NEW YORK UNIVERSITY · 1990 · $143,693

## Abstract

The epidermis performs two important functions--to provide strong
physical protection and to serve as a permeability barrier.  To perform
the first function the epidermis synthesizes large amounts of keratin
proteins which form the predominant (>90%) component in cornified cells.
These keratins belong to a multigene family.  They can be divided into an
acidic (also known as Type I) and a basic (Type II) subfamily, and it has
been shown that any acidic keratin can combine with any basic keratin to
form 10 nm filaments.  To gain insights into the nature of the forces
responsible for filament formation, we will mutate systemically several
selected amino acids in K18 keratin by site-directed mutagenesis, and
test the mutant keratins' ability to polymerize with the normal partner,
keratin K8.  The test will be performed by transfecting the normal or
mutant K18 cDNA into L cells artificially constructed to express K8
keratin, followed by immunofluorescent staining and EM analysis.  It is
expected that some of the mutant keratin K18 will produce abnormal
keratin filaments with altered diameter, degree of lateral aggregation,
or even being arrested at different stages of filament assembly.  These
results will shed light on the subunit interaction and dynamic aspects of
keratin filament formation.  To perform the other major function, i.e.,
as a permeability barrier, the epidermis elaborates in the granular layer
numerous lamellar granules (200 nm) which discharge their contents into
the intercellular space.  Since these granules are difficult to purify,
relatively little is known about their detailed biochemical composition.
Using a panel of monoclonal antibodies, we have identified a 25K protein
in lamellar granules.  Experiments are designed to characterize this
novel epidermal differentiation marker both on a protein and a
cDNA/genomic DNA level.  Results from these studies may yield new
insights into an important regulatory step during terminal stages of
keratinization, as well as on the formation of epidermal permeability
barrier.

## Key facts

- **NIH application ID:** 3156867
- **Project number:** 5R01AR034511-07
- **Recipient organization:** NEW YORK UNIVERSITY
- **SAM.gov UEI:** NX9PXMKW5KW8
- **Principal Investigator:** Tung-Tien Sun
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $143,693
- **Award type:** 5
- **Project period:** 1984-07-01 → 1992-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156867

## Citation

> US National Institutes of Health, RePORTER application 3156867, MARKERS OF EPIDERMAL DIFFERENTIATION (5R01AR034511-07). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3156867. Licensed CC0.

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