Stephen J. Gould, Ph.D.

  • Director, Graduate Program in Biological Chemistry
  • Professor of Biological Chemistry

Research Interests

Exosome biogenesis and engineering; cell biology of SARS-CoV-2 spike; development of exosome-based vaccines and therapeutics; creation of synthetic signal transduction modulators more


Stephen J. Gould is a professor in the Department of Biological Chemistry at the Johns Hopkins University School of Medicine. His research interests lie at the intersection of protein trafficking and human disease, with active research projects focusing on the biogenesis and in vivo functions of exosomes, development of new technologies for cell and exosome engineering, creation of exosome-based vaccines and therapeutics, invention of synthetic signal modulation systems, and the cell biology of SARS-CoV-2 spike.

Dr. Gould received his B.S. in Marine Biology from University of California, Santa Barbara, earned his Ph.D. in Biology from the University of California, San Diego, and also did his post-doctoral training at University of California San Diego. Steve joined the Hopkins faculty in 1991 as an assistant professor, became an associate professor in 1998, and full professor in 2002.

Steve has authored more than 100 peer-reviewed publications, is Founder and President of the American Society for Exosomes and Microvesicles, is a Founding Member of the Board of Directors of the American Association for Extracellular Vesicles, and Editor of, a continuously updated source of information on exosomes and other extracellular vesicles. Dr. Gould has for 14 years organized the annual meeting of US exosome scientists, developed the first graduate-level exosome class, which is taught by leading exosome researchers from across the globe, and has delivered scores of invited lectures on exosome biogenesis and other aspects of cell biology. more


  • Director, Graduate Program in Biological Chemistry
  • Professor of Biological Chemistry

Departments / Divisions

Centers & Institutes



  • Ph.D.; University of California - San Diego - School of Medicine - La Jolla (California) (1989)
  • B.A.; University of California (Santa Barbara) (California) (1984)

Additional Training

  • University of California, San Diego, CA, 1991

Research & Publications

Research Summary

Dr. Gould’s lab works on four distinct yet overlapping projects:

  1. Exosome Biogenesis: Exosomes are small secreted vesicles of ~100 nm in size that play critical roles in human health and disease. We want to understand the molecular mechanisms of exosome cargo protein budding and exosome biogenesis, and their inhibition by endocytosis, plasma membrane-to-lysosome sorting, and lysosome function.
  2. Exosome Engineering: Exosomes are the only bionormal nanovesicle, which makes them an ideal delivery vehicle for vaccines, biologics, and drugs. Our laboratory combines the latest advances in cell and exosome engineering to create exosome-based vaccines and biologics.
  3. Synthetic Signaling: Together with the neuroscientist Michael Caterina (JHU SOM), we invent signal-triggered protein trafficking systems, for use as in vivo tools to elucidate mechanisms of signal transduction, and as genetically-encoded therapies to treat chronic pain.
  4. SARS-CoV-2 spike: We recently discovered that SARS-CoV-2 Spike is a lysosomal protein, and that the earliest mutation in spike, D614G, arose to correct a defect in spike trafficking to lysosomes. Our lab seeks to understand the mechanisms of spike sorting to lysosomes and how this contributes to the formation and egress of SARS-CoV-2, and its endolysosomal route of infection.

Selected Publications

Y. Ai, C. Guo, M. Garcia-Contreras, L. Sanchez Buitrago, A. Saftics, O. Shodubi, S. Raghunandan, J. J. Xu, S.-J. Tsai, Y. Dong, R. Li, T. Jovanovic-Talisman, S. J. Gould, Syntenin and CD63 Promote Exosome Biogenesis from the Plasma Membrane by Blocking Cargo Endocytosis. bioRxiv (2023)

C. Guo, S. J. Tsai, Y. Ai, M. Li, E. Anaya, A. Pekosz, A. Cox, S. J. Gould, The D614G mutation redirects SARS-CoV-2 spike to lysosomes and suppresses deleterious traits of the furin cleavage site insertion mutation. Science Advances 8, eade5085 (2022)

F. K. Fordjour, C. Guo, Y. Ai, G. G. Daaboul, S. J. Gould, A shared, stochastic pathway mediates exosome protein budding along plasma and endosome membranes. Journal of Biological Chemistry, 102394 (2022)

S. J. Tsai, Y. Ai, C. Guo, S. J. Gould, Degron-tagging of BleoR and other antibiotic-resistance genes selects for higher expression of linked transgenes and improved exosome engineering. Journal of Biological Chemistry, 101846 (2022)

C. Guo, F. K. Fordjour, S. J. Tsai, J. C. Morrell, S. J. Gould, Choice of selectable marker affects recombinant protein expression in cells and exosomes. Journal of Biological Chemistry, 100838 (2021)

D. M. Pegtel, S. J. Gould, Exosomes. Annual Review of Biochemistry 88, 487-514 (2019)

Academic Affiliations & Courses

Graduate Program Affiliation

Graduate Program in Biological Chemistry

Graduate Program in Biochemistry, Cell, and Molecular Biology

Courses and Syllabi

  • Translational Intersession in Metabolism
  • Exosomes and other extracellular vesicles
  • "Metabolism" in Scientific Foundations of Medicine

Activities & Honors


  • Rose Johnstone Memorial Lectureship, McGill University, 2010
  • Powell Foundation Fellowship, 1989


  • American Society for Exosomes and Microvesicles
  • American Association for Extracellular Vesicles
  • International Society for Extracellular Vesicles

Professional Activities

  • President, American Society of Exosomes and Microvesicles, 2012
  • Board of Directors, American Association for Extracellular Vesicles, 2022
  • Editor,

Videos & Media

Recent News Articles and Media Coverage

How Sars-cov-2 Evolved To Counter Its Own Weaknesses, The Hub (January 18, 2023)

Patient Ratings & Comments

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