David M. Sabatini | |
---|---|
Born | |
Nationality | American |
Citizenship | United States |
Alma mater | Brown University Johns Hopkins School of Medicine |
Known for | Co-discovery and study of mTOR |
Scientific career | |
Fields | Biochemistry Cell Biology |
Institutions | Whitehead Institute Massachusetts Institute of Technology Broad Institute |
Doctoral advisor | Solomon H. Snyder |
David M. Sabatini (born January 27, 1968) is an American scientist and a former professor of biology at the Massachusetts Institute of Technology. From 2002 to 2021, he was a member of the Whitehead Institute for Biomedical Research. He was also an investigator of the Howard Hughes Medical Institute from 2008 to 2021 and was elected to the National Academy of Sciences in 2016. He is known for his contributions in the areas of cell signaling and cancer metabolism, most notably the co-discovery of mTOR. [1]
In 2021 and 2022, Sabatini was fired from the Howard Hughes Medical Institute and resigned his positions at the Whitehead Institute and the Massachusetts Institute of Technology, following allegations of sexual harassment. [2] [3] [4] Sabatini denies the allegations.
David M. Sabatini was born and raised in New York to David D. Sabatini and Zulema Sabatini, both Argentine immigrants from Buenos Aires. He obtained his B.S. from Brown University followed by both his MD and his Ph.D. at Johns Hopkins School of Medicine, where he worked in the lab of Solomon H. Snyder. He joined the Whitehead Institute as a Whitehead Fellow in 1997, the same year he graduated from Johns Hopkins. [5] In 2002 he became an assistant professor at MIT and a Member of the Whitehead Institute. He was promoted to tenured professor in 2006.
Sabatini's father, David D. Sabatini, is a cell biologist and professor at New York University. His younger brother, Bernardo L. Sabatini, is a neuroscientist and professor at Harvard Medical School. [5] [6]
Sabatini is the scientific founder of Navitor, [7] Raze Therapeutics, [8] and KSQ Therapeutics. [9]
In April 2021, after a new director of the Whitehead Institute where Sabatini worked had initiated a sexual harassment survey, a former graduate student at the institute came forward with sexual harassment allegations against him. [10]
In August 2021, following an investigation of the complaints by an outside law firm, Sabatini was forced to resign from the Whitehead Institute and was fired from the Howard Hughes Medical Institute which had funded his research. [11] [2] [12] Sabatini denies that the alleged behavior was sexual harassment, claims that the investigation was biased, and has filed a defamation lawsuit against the Whitehead Institute, its director and his accuser. [3] [10] [4] His accuser responded with a countersuit, claiming that he coerced her into sex and that the atmosphere in his lab was sexually charged and toxic. [10]
MIT placed Sabatini on administrative leave while it conducted its own investigation. [13] This investigation concluded that Sabatini had violated its policies on sexual relationships in the workplace, finding that he "engaged in a sexual relationship with a person over whom he held a career-influencing role", and gave a recommendation to revoke tenure. Sabatini resigned from his position at MIT in April 2022. [3] [13]
In 2022, Sabatini was under consideration for a position at the NYU Grossman School of Medicine. [14] After significant protests from students and some faculty over the sexual harassment allegations, he withdrew his name from consideration. [4] [15] [16]
In February 2023, Bill Ackman and an unnamed partner announced $25 million to fund Sabatini's research, though it is unclear if he could successfully find an institution willing to host his lab or if one could be built independently. [17] [18] By November 2023, Sabatini had accepted a position at the Institute of Organic Chemistry and Biochemistry (IOCB) of the Czech Academy of Sciences in Prague, [19] [20] and in April 2024 it was announced that IOCB would open a Boston branch, where it was planned that Sabatini would spend part of his time. [21]
As a graduate student in Solomon Snyder's Lab at Johns Hopkins, Sabatini began working on understanding the molecular mechanism of rapamycin; a macrolide antibiotic discovered in the soil of Easter Island that has potent antifungal, immunosuppressive, and anti-tumorigenic properties. [5] Although the TOR/DRR genes had been identified in 1993 as conferring rapamycin resistance in budding yeast, the direct target of rapamycin and its mechanism of action in mammals was unknown. [22] [23] In 1994, Sabatini used rapamycin and its binding partner FKBP12 to purify the mechanistic Target of Rapamycin (mTOR) protein from rat brain, showing it to be the direct target of rapamycin in mammals and the homolog of the yeast TOR/DRR genes. [5]
Since starting his own lab at the Whitehead Institute in 1997, Sabatini has made numerous key contributions to the understanding of mTOR function, regulation, and importance in diseases such as cancer. [24] For example, his lab discovered the mTORC1 [25] and mTORC2 [26] multi-protein complexes, the nutrient sensing Rag GTPase pathway upstream of mTORC1, [27] as well as the direct amino acid sensors Sestrin [28] [29] and CASTOR. [30] [31]
Sabatini's research interests have expanded in recent years to include cancer metabolism as well as technology development surrounding the use of high-throughput genetic screens in human cells, most notably through the use of RNA interference [32] and the CRISPR-Cas9 system. [33]
Susan Lee Lindquist, ForMemRS was an American professor of biology at MIT specializing in molecular biology, particularly the protein folding problem within a family of molecules known as heat-shock proteins, and prions. Lindquist was a member and former director of the Whitehead Institute and was awarded the National Medal of Science in 2010.
Sirolimus, also known as rapamycin and sold under the brand name Rapamune among others, is a macrolide compound that is used to coat coronary stents, prevent organ transplant rejection, treat a rare lung disease called lymphangioleiomyomatosis, and treat perivascular epithelioid cell tumor (PEComa). It has immunosuppressant functions in humans and is especially useful in preventing the rejection of kidney transplants. It is a mechanistic target of rapamycin (mTOR) kinase inhibitor that reduces the sensitivity of T cells and B cells to interleukin-2 (IL-2), inhibiting their activity.
Everolimus, sold under the brand name Afinitor among others, is a medication used as an immunosuppressant to prevent rejection of organ transplants and as a targeted therapy in the treatment of renal cell cancer and other tumours.
The mammalian target of rapamycin (mTOR), also referred to as the mechanistic target of rapamycin, and sometimes called FK506-binding protein 12-rapamycin-associated protein 1 (FRAP1), is a kinase that in humans is encoded by the MTOR gene. mTOR is a member of the phosphatidylinositol 3-kinase-related kinase family of protein kinases.
The tumor suppressor gene FLCN encodes the protein folliculin, also known as Birt–Hogg–Dubé syndrome protein, which functions as an inhibitor of Lactate Dehydrogenase-A and a regulator of the Warburg effect. Folliculin (FLCN) is also associated with Birt–Hogg–Dubé syndrome, which is an autosomal dominant inherited cancer syndrome in which affected individuals are at risk for the development of benign cutaneous tumors (folliculomas), pulmonary cysts, and kidney tumors.
RHEB also known as Ras homolog enriched in brain (RHEB) is a GTP-binding protein that is ubiquitously expressed in humans and other mammals. The protein is largely involved in the mTOR pathway and the regulation of the cell cycle.
Ribosomal protein S6 kinase beta-1 (S6K1), also known as p70S6 kinase, is an enzyme that in humans is encoded by the RPS6KB1 gene. It is a serine/threonine kinase that acts downstream of PIP3 and phosphoinositide-dependent kinase-1 in the PI3 kinase pathway. As the name suggests, its target substrate is the S6 ribosomal protein. Phosphorylation of S6 induces protein synthesis at the ribosome.
Regulatory-associated protein of mTOR also known as raptor or KIAA1303 is an adapter protein that is encoded in humans by the RPTOR gene. Two mRNAs from the gene have been identified that encode proteins of 1335 and 1177 amino acids long.
Rapamycin-insensitive companion of mammalian target of rapamycin (RICTOR) is a protein that in humans is encoded by the RICTOR gene.
Angelika Amon was an Austrian American molecular and cell biologist, and the Kathleen and Curtis Marble Professor in Cancer Research at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts, United States. Amon's research centered on how chromosomes are regulated, duplicated, and partitioned in the cell cycle. Amon was elected to the American Academy of Arts and Sciences in 2017.
Target of rapamycin complex subunit LST8, also known as mammalian lethal with SEC13 protein 8 (mLST8) or TORC subunit LST8 or G protein beta subunit-like, is a protein that in humans is encoded by the MLST8 gene. It is a subunit of both mTORC1 and mTORC2, complexes that regulate cell growth and survival in response to nutrient, energy, redox, and hormonal signals. It is upregulated in several human colon and prostate cancer cell lines and tissues. Knockdown of mLST8 prevented mTORC formation and inhibited tumor growth and invasiveness.
mTOR inhibitors are a class of drugs used to treat several human diseases, including cancer, autoimmune diseases, and neurodegeneration. They function by inhibiting the mammalian target of rapamycin (mTOR), which is a serine/threonine-specific protein kinase that belongs to the family of phosphatidylinositol-3 kinase (PI3K) related kinases (PIKKs). mTOR regulates cellular metabolism, growth, and proliferation by forming and signaling through two protein complexes, mTORC1 and mTORC2. The most established mTOR inhibitors are so-called rapalogs, which have shown tumor responses in clinical trials against various tumor types.
mTORC1, also known as mammalian target of rapamycin complex 1 or mechanistic target of rapamycin complex 1, is a protein complex that functions as a nutrient/energy/redox sensor and controls protein synthesis.
mTOR Complex 2 (mTORC2) is an acutely rapamycin-insensitive protein complex formed by serine/threonine kinase mTOR that regulates cell proliferation and survival, cell migration and cytoskeletal remodeling. The complex itself is rather large, consisting of seven protein subunits. The catalytic mTOR subunit, DEP domain containing mTOR-interacting protein (DEPTOR), mammalian lethal with sec-13 protein 8, and TTI1/TEL2 complex are shared by both mTORC2 and mTORC1. Rapamycin-insensitive companion of mTOR (RICTOR), mammalian stress-activated protein kinase interacting protein 1 (mSIN1), and protein observed with rictor 1 and 2 (Protor1/2) can only be found in mTORC2. Rictor has been shown to be the scaffold protein for substrate binding to mTORC2.
Michael Nip Hall is an American-Swiss molecular biologist and professor at the Biozentrum of the University of Basel, Switzerland. He discovered TOR, a protein central for regulating cell growth.
Nitrogen permease regulator-like 3 is a protein that in humans is encoded by the NPRL3 gene.
Bernardo L. Sabatini is an American neuroscientist who is the Alice and Rodman W. Moorhead III Professor of Neurobiology at Harvard Medical School.
The Ragulator-Rag complex is a regulator of lysosomal signalling and trafficking in eukaryotic cells, which plays an important role in regulating cell metabolism and growth in response to nutrient availability in the cell. The Ragulator-Rag Complex is composed of five LAMTOR subunits, which work to regulate MAPK and mTOR complex 1. The LAMTOR subunits form a complex with Rag GTPase and v-ATPase, which sits on the cell’s lysosomes and detects the availability of amino acids. If the Ragulator complex receives signals for low amino acid count, it will start the process of catabolizing the cell. If there is an abundance of amino acids available to the cell, the Ragulator complex will signal that the cell can continue to grow. Ragulator proteins come in two different forms: Rag A/Rag B and Rag C/Rag D. These interact to form heterodimers with one another.
Joseph Heitman is an American physician-scientist focused on research in genetics, microbiology, and infectious diseases. He is the James B. Duke Professor and Chair of the Department of Molecular Genetics and Microbiology at Duke University School of Medicine.
Phosphatidylinositol 3-phosphate-binding protein 2 (Pib2) is a yeast protein involved in the regulation of TORC1 signaling and lysosomal membrane permeabilization. It is essential for the reactivation of TORC1 following exposure to rapamycin or nutrient starvation.