David J Glass

David J. Glass (born 1961) is an American biomedical scientist who has worked on elucidating the mechanisms by which skeletal muscle undergoes hypertrophy and atrophy. He played a role in discovering the "MuSK protein receptor" (Muscle Specific-kinase) that is responsible for formation of the neuromuscular junction, and d the mechanism by which MuSK is activated - it's a receptor for the motor neuron-secreted protein, agrin. He also wrote a book aimed at teaching biology graduate students how to design their experiments.

Glass is an elected member of the National Academy of Sciences and the American Association for the Advancement of Science. Earlier, he was elected to the American Society for Clinical Investigation.

Glass is also a playwright. His play, "Love + Science" was produced Off-Broadway in New York City in 2023. . His most recent play is "Spare Parts," which was staged at Theatre Row (New York City) from March through April of 2026.

Scientific career

Glass helped to identify the mechanism by which muscles connect to nerves. Glass and his colleagues, including George Yancopoulos, discovered a receptor tyrosine kinase which they named "MuSK" (Muscle Specific Kinase, or MuSK protein). They went on to show that MuSK is required for the formation of the neuromuscular junction, the key structure which allows motor neurons to induce skeletal muscle to contract. They next demonstrated that the ligand for MuSK is agrin, a protein secreted by the motor neuron to induce formation of the neuromuscular junction.

Glass also cloned receptors for neurotrophic factors, such as TrkB, the receptor for BDNF, and showed that they were sufficient to mediate signaling without the requirement of the Low affinity Nerve Growth Factor receptor (LNGFR).

Glass identified the E3 ubiquitin ligases, MuRF1 and FBXO32/Atrogin1/MAFbx, which are upregulated during skeletal muscle atrophy; mice which are null for these ligases were found to have less loss of muscle under atrophic conditions. One substrate of MuRF1 is Myosin heavy chain (MHC), a major component of the sarcomere. Therefore, by degrading MHC, MuRF1 breaks down a major component of skeletal muscle, inducing muscle to atrophy.

Glass further identified the Akt pathway as being critical for inducing skeletal muscle to undergo hypertrophy. Briefly, the growth factor IGF1 induces muscle to hypertrophy, or expand in size, via the increase in size of the pre-existing muscle fibers. This happens by IGF1/IGF1R/PI3K/Akt signaling, which in turn both activates the mTOR pathway to increase protein synthesis, and inhibits the transcriptional upregulation of MuRF1, by blocking nuclear translocation of the Foxo family of transcription factors.

Book on experimental design, and a critique of hypothesis-testing

David Glass is the author of a book aimed at teaching students how to design biology experiments, titled "Experimental Design for Biologists." The book is in its 2nd edition, published by Cold Spring Harbor Laboratory Press. In the initial chapters of his book, Glass argues against hypothesis testing as a framework for performing experiments, and instead suggests that experiments should initially be framed with questions, in order to stimulate the production of data. Once there is data, then that can be used to produce a model, which can next be tested for its predictive power. While he doesn't mention Bayesian reasoning, these suggestions are reminiscent of Bayesian methods. Glass also argued against hypothesis testing in an article titled, "A critique of the hypothesis, and a defense of the question, as a framework for experimentation.".

Editorial role

Glass was the founding editor-in-chief of the Elsevier journal Skeletal Muscle.

Honors and awards

Elected (2024) to the National Academy of Sciences . Elected (2021) to the American Association for the Advancement of Science. President, Society for Muscle Biology (SMB) 2025 Elected (2024), Academy of Geroscience Elected (2004) to the American Society for Clinical Investigation. Elected (2024) member to the New York Academy of Medicine.

Theater

Glass wrote "Love + Science", which was produced Off-Broadway at City Center in New York City in the summer of 2023, and was reviewed by the New York Times, and by the editor-in-chief of Science.

His most recent play is "Spare Parts," which was presented at Theatre Row (New York City) in March though April of 2026.

Selected papers