# Determining Structure and Function of Human Skin Barrier Proteins Using X-ray Crystallography

> **NIH NIH K08** · YALE UNIVERSITY · 2020 · $150,697

## Abstract

PROJECT SUMMARY
The human skin barrier does not always function as intended; in fact, defects in the outer layer of human
skin account for a significant number of health problems for people living in the United States. As one
example, it is estimated that up to 90 million Americans suffer from some form of atopic dermatitis. Atopic
dermatitis and other forms of severely dry skin, such as ichthyosis vulgaris, are associated with defects or
mutations in profilaggrin and its processed fragment, filaggrin. Mutations in keratin 1 and keratin 10 proteins
also account for a variety of inherited skin disorders manifested by red, dry, scaly skin. Together,
profilaggrin and keratins 1 and 10 are critical proteins involved in the stratum corneum of human skin, and
elucidating the biochemistry behind their function is important for improving our understanding of how the
human skin barrier works. The hope is that advancing our knowledge of how protein structure dictates
function in the stratum corneum will generate new methods for treatment of human skin diseases.
This proposal aims to address a deficiency in our understanding of the atomic resolution structure of key
epidermal proteins, namely profilaggrin and keratins 1 and 10. In particular, it is still unclear (1) what the
precise mechanisms are for profilaggrin binding to target proteins; (2) is there correlation between structure
and function of the profilaggrin B domain; (3) does profilaggrin interaction with target proteins direct specific
events in terminal epidermal differentiation; (4) what are the molecular mechanisms behind keratin
intermediate filament aggregation; and (5) can enhanced structural knowledge of key skin barrier proteins
pave the way for newly designed topical therapeutics. Given the direct association of profilaggrin and
keratins 1 and 10 with multiple human diseases, we believe focusing our studies on these medically
important proteins will help us address these outstanding questions.
In this project, we examine the biochemical and structural properties of key proteins involved in a functional
human skin barrier. Our first aim uses x-ray crystallography and biochemical analysis techniques to
determine the structural basis of binding between profilaggrin and one of its targets, annexin II. The second
aim examines the x-ray crystal structure of profilaggrin in the absence of bound molecules and performs
mutational analysis on key inter-EF-hand linker residues in order to understand the functional role of this
protein region. The third aim examines the structural basis for keratin intermediate filament interaction with
different parts of the profilaggrin molecule using x-ray crystallography and biochemical techniques.
Accomplishing these aims will provide novel insight into the principle biochemistry and atomic resolution
structure of key epidermal proteins involved in maintaining the integrity of the human skin barrier.

## Key facts

- **NIH application ID:** 9953947
- **Project number:** 5K08AR070290-05
- **Recipient organization:** YALE UNIVERSITY
- **Principal Investigator:** Christopher Gerard Bunick
- **Activity code:** K08 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $150,697
- **Award type:** 5
- **Project period:** 2016-07-01 → 2021-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9953947

## Citation

> US National Institutes of Health, RePORTER application 9953947, Determining Structure and Function of Human Skin Barrier Proteins Using X-ray Crystallography (5K08AR070290-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9953947. Licensed CC0.

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