# Structure and Function in alpha-Dystroglycan Glycosylation

> **NIH NIH R01** · UNIVERSITY OF GEORGIA · 2023 · $418,257

## Abstract

SUMMARY
Dystroglycanopathies, a subset of congenital muscular dystrophies, impact more than 1:100,000 individuals and
encompass a range of disorders with patient sequalae ranging from mild muscular dystrophy with near normal
lifespan to severe muscular dystrophy with major neural and ocular defects leading to death in the first few years
of life. The vast majority of genetically-defined dystroglycanopathies are a result of mutations in genes encoding
enzymes of the O-mannosylation pathway, specifically the so-called M3 pathway. To date, the M3 pathway,
which consists of approximately a dozen enzymes, has only been found to elaborate O-mannose glycans on a
small subset of threonine residues on the peripheral membrane protein alpha-dystroglycan that is involved in a
complex that bridges the extracellular matrix to the actin cytoskeleton across the plasma membrane. In the prior
funding period, we and others elucidated the M3 structure that terminates in a repeating disaccharide referred
to as matriglycan. We have recently demonstrated that matriglycan alone, absent the underlying M3 glycan and
alpha-dystrolgycan, is both necessary and sufficient to bind LG domain-containing proteins as well as facilitate
binding and infection by certain arenaviruses, such as Lassa virus. Here, we seek to address key remaining
basic science issues especially those that would facilitate early stage clinical investigations, including substrate
enhancement therapy, AAV gene transfer therapy, and novel gene identification. Thus, we will test the specificity
of M3 enzymes including testing whether M3 glycans can be built on other non-O-Man glycan structures (A1).
Further testing specificity and to address the evolutionary quandary of building an entire M3 pathway for one
protein substrate, we will test whether other proteins contain M3 glycan structures, which could be involved in
the phenotypes of certain dystroglycanopathies (A1). Driven by our desire to understand the structure-function
relationship of M3 enzymes as well as to inform clinical collaborators, we will investigate the impact of missense
variants on M3 enzymes with regards to stability and activity using our established protocols (A2). Further, given
the high carrier frequency (1:150 in Northern Europe) of the L276I FKTN variant, we will investigate whether
heterozygous and homozygous cell lines harboring this variant are less susceptible to matriglycan-dependent
pseudovirus infection (A2). Finally, given that ~1/3 of all dystroglycanopathies are of unknown genetic etiology,
we will conduct an unbiased CRISPR/Cas9 screen in relevant human cell lines to identify novel gene products
that are required for functional glycosylation of alpha-dystroglycan (A3). Coupled to this unbiased approach, we
will also investigate the pathway for CDP-ribitol synthesis, that is necessary for M3 glycan synthesis, to identify
gene products involved that may be responsible for a subset of the unknown cases of dystroglycanopathy ...

## Key facts

- **NIH application ID:** 10678139
- **Project number:** 2R01GM111939-09
- **Recipient organization:** UNIVERSITY OF GEORGIA
- **Principal Investigator:** Lance Wells
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $418,257
- **Award type:** 2
- **Project period:** 2014-08-01 → 2027-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10678139

## Citation

> US National Institutes of Health, RePORTER application 10678139, Structure and Function in alpha-Dystroglycan Glycosylation (2R01GM111939-09). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10678139. Licensed CC0.

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