Thomas F. J. Martin

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Reference excerpt

Thomas F. J. Martin is an American biochemist and cell biologist. He is best known for his discovery and characterization of the CAPS (Calcium-dependent Activator Protein for Secretion, also known as CADPS) family of proteins, which serve as essential priming factors in regulated exocytosis-the calcium-triggered release of hormones and neurotransmitters from dense-core vesicles in neuroendocrine and neural cells. He is Professor Emeritus in the Department of Biochemistry at the University of Wisconsin–Madison, where he held two named professorships and conducted research that helped elucidate the molecular machinery of vesicle priming and SNARE-mediated membrane fusion.

Early life and education Martin received his A.B. degree from Cornell University and his Ph.D. from Harvard University.

Career Martin joined the University of Wisconsin–Madison faculty in 1978 as Assistant Professor in Zoology and became Professor of Biochemistry in 1994. He held the Wasson Professorship in Biochemistry and the Earl W. Sutherland Professorship in Biochemistry. He became Professor Emeritus in 2022.

Research Martin's laboratory investigated signal transduction mechanisms for peptide hormones that contributed to finding that receptor-regulated hydrolysis of the inositol phospholipid PI(4,5)P2 was central to hormone signaling. His later work on intracellular signaling again revealed the importance of inositol phospholipids as well as some of the protein machinery underlying Ca2+-triggered exocytosis in neuroendocrine and neural cells. In 1992, working with colleagues, he identified a novel 145 kDa cytosolic protein-later named CAPS-that reconstitutes calcium-regulated secretion in permeable neuroendocrine cells. Work in his lab in 1995 also discovered that the phosphoinositide PI(4,5)P2 was essential for regulated vesicle exocytosis. Subsequent work established CAPS as a PI(4,5)P2-binding protein that acts at a pre-fusion step to promote assembly of SNARE complexes and vesicle priming. His group further demonstrated that CAPS (and its paralog Munc13) functions as a "CATCHR" protein that drives trans-SNARE complex formation through direct syntaxin interactions, and that CAPS is required for dense-core vesicle exocytosis in genetic models such as Caenorhabditis elegans and Drosophila melanogaster. This body of work, along with later reviews by Martin and colleagues, has clarified how PI(4,5)P2-binding effectors coordinate multiple stages of vesicle exocytosis and has informed research on secretion defects in neurological and endocrine disorders.

Awards and honors Wasson Professorship in Biochemistry Earl W. Sutherland Professorship in Biochemistry NIH MERIT Award, for long-term studies on stages of regulated exocytosis McKnight Neuroscience Investigator Award, for research on the molecular mechanisms of neurosecretion

Selected publications Martin, Thomas F.; Kowalchyk, Judith A. (1983). "Thyrotropin-releasing hormone rapidly activates the phosphodiester hydrolysis of polyphosphoinositides in GH3 pituitary cells. Evidence for the role of a polyphosphoinositide-specific phospholipase C in hormone action". Journal of Biological Chemistry. 258 (24): 14816–14822. doi:10.1016/S0021-9258(17)43734-3. PMID 6317674. Walent, J. H.; Porter, B. W.; Martin, T. F. J. (1992). "A novel 145 kDa brain cytosolic protein reconstitutes Ca2+-regulated secretion in permeable neuroendocrine cells". Cell. 70 (5): 765–775. doi:10.1016/0092-8674(92)90310-9. PMID 1516133. Hay, J. C.; Fisette, P. L.; Jenkins, G. H.; Fukami, K.; Takenawa, T.; Anderson, R. A.; Martin, T. F. (1995). "ATP-dependent inositide phosphorylation required for Ca2+-activated secretion". Nature. 374 (6518): 173–177. Bibcode:1995Natur.374..173H. doi:10.1038/374173a0. PMID 7877690. Loyet, K. M.; Kowalchyk, J. A.; Chaudhary, A.; Chen, J.; Prestwich, G. D.; Martin, T. F. (1998). "Specific binding of phosphatidylinositol 4,5-bisphosphate to calcium-dependent activator protein for secretion (CAPS), a potential phosphoinositide effector protein for regulated exocytosis". Journal of Biological Chemistry. 273 (14): 8337–8343. doi:10.1074/jbc.273.14.8337. PMID 9525942. Renden, R.; Berwin, B.; Davis, W.; Ann, K.; Chin, C. T.; Kreber, R.; Ganetzky, B.; Martin, T. F.; Broadie, K. (2001). "Drosophila CAPS is an essential gene that regulates dense-core vesicle release and synaptic vesicle fusion". Neuron. 31 (3): 421–437. doi:10.1016/s0896-6273(01)00382-8. PMID 11516399. Grishanin, R. N.; Kowalchyk, J. A.; Klenchin, V. A.; Ann, K.; Earles, C. A.; Chapman, E. R.; Gerona, R. R.; Martin, T. F. J. (2004). "CAPS Acts at a Prefusion Step in Dense-Core Vesicle Exocytosis as a PIP2 Binding Protein". Neuron. 43 (4): 551–562. doi:10.1016/j.neuron.2004.07.028. PMID 15312653. Speese, Sean D.; Petrie, Matt; Schuske, Kim; Ailion, Michael; Ann, Kyoungsook; Iwasaki, Kouichi; Jorgensen, Erik M.; Martin, Thomas F. J. (2007). "UNC-31 (CAPS) Is Required for Dense-Core Vesicle But Not Synaptic Vesicle Exocytosis in Caenorhabditis elegans". Journal of Neuroscience. 27 (23): 6150–6162. doi:10.1523/JNEUROSCI.1466-07.2007. PMC 6672160. PMID 17553995. James, Declan J.; Kowalchyk, Judith A.; Daily, Nathan J.; Petrie, Matt; Martin, Thomas F. J. (2009). "CAPS drives trans-SNARE complex formation and membrane fusion through syntaxin interactions". Proceedings of the National Academy of Sciences of the United States of America. 106 (41): 17308–17313. doi:10.1073/pnas.0900758106. PMC 2765074. PMID 19805029. James, Declan J.; Martin, Thomas F. J. (2013). "CAPS and Munc13: CATCHRs that SNARE Vesicles". Frontiers in Endocrinology. 4: 187. doi:10.3389/fendo.2013.00187. PMC 3849599. PMID 24363652. Martin, Thomas F. J. (2015). "PI(4,5)P2-binding effector proteins for vesicle exocytosis". Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids. 1851 (6): 785–793. doi:10.1016/j.bbalip.2014.09.017. PMC 4380529. PMID 25280637. Yamaga, M.; Martin, T. F. J. (2025). "PI(4,5)P2 is a master regulator for Ca2+-triggered vesicle exocytosis". Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids. 1870 (6) 159651. doi:10.1016/j.bbalip.2025.159651. PMC 12341446. PMID 40543808.

References

Worked examples

Example 1 — a first encounter with Thomas F. J. Martin

Start with the simplest possible case. Write down what Thomas F. J. Martin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Thomas F. J. Martin before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Thomas F. J. Martin ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Thomas F. J. Martin

In research: Thomas F. J. Martin appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Thomas F. J. Martin in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Thomas F. J. Martin is common in secondary-school and first-year university syllabi. It links to neighbouring topics 20th-century American scientists, 21st-century American scientists, American biochemists, so understanding it makes those chapters shorter.
In everyday life: Look for Thomas F. J. Martin outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Thomas F. J. Martin in 20 minutes

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Frequently asked questions

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