People

Pradipta Ghosh, MD

Taking the first steps: Those who knew Pradipta as a child would agree that she is easily bored if not constantly challenged. Building a knowledge base that is very broad and deep was her way to take on the challenge in exploring anything that she knew little or nothing about. After graduating as the Best Outgoing Student in a nationwide ranking, from the top medical school in India, Pradipta came to US in 2001 in search of the next challenge, that of a career in biomedical science. This twist in career was prompted by a famous quote that she had stumbled upon -- "Medicine is not only an art; it is also a science. It does not consist of compounding pills and plasters; it deals with the very processes of life, which must be understood before they may be guided". Determined to get trained in a good laboratory, she applied to Universities in US with little or no hope of hearing back. Her dream materialized when her resume trickled through the system and fell in the hands of Stuart Kornfeld at Washington University St Louis, MO, a seasoned physician-scientist and a great mentor, an astute judge of character and talent, who agreed to give Pradipta an opportunity to train in his laboratory. Pradipta was quick to realize that this rare opportunity comes with extraordinary challenges ahead because she was about to enter a dual-career path, that of a physician-scientist, with no prior training as a scientist and years of rigorous internship, residency and fellowship in US ahead of her. She was introduced to experimental medicine in the Kornfeld laboratory, where she took the very first steps in her scientific career. Soon her vocation became her passion and what followed during the next 18 months was nothing short of magic. Her work investigated how adaptor proteins, GGAs and AP1&2, affected sorting of Mannose-6 Phosphate Receptors (MPRs) and directly led to the discovery of a layer of complexity in the multi-step sorting of the receptor in-and-out of the Golgi. Through her publications within the next year, a novel paradigm emerged in the field of protein trafficking where series of ying-yang phospho- and dephosphorylation events regulate each step of receptor trafficking based on the temporospatial distribution of the respective kinases or phosphatases. If St Louis winters were cold, or summers hot, Pradipta would not know because she was in the lab round-the-clock acquiring the scientific tools and building her technical expertise. She recalls that the learning curve was steep, but she enjoyed every moment of the journey, gaining unique perspective and broadening her horizon with every passing day. She describes her time spent in the Kornfeld lab as the most formative years of her scientific career because it served as a solid foundation for the years to come.

Building on the foundation: In 2003, Pradipta moved to University of California, San Diego (UCSD) to begin her clinical training in Internal Medicine. After fast-tracking through her internship and residency in the physican-scientist training pathway, she joined the UC San Diego Gastroenterology Fellowship Program in 2005. A year later, she began her postdoctoral research training in the George Palade laboratories under the mentorship of Dr. Marilyn G. Farquhar, PhD Equipped with the skills of a biochemist, this is where she honed her skills as a cellular and molecular biologist, and further broadened her horizon by incorporating systems biology, computational modeling and bioinformatics into her research program. Her postdoctoral work on a newly discovered protein, GIV/Girdin, established the presence of a novel class of signaling molecules and unraveled hitherto unknown functions of these molecules in cell biology and pathophysiology. In 2008 she graduated from the Gastroenterology fellowship program and joined as an Assistant Professor on tenure track in the department of Medicine at UC San Diego. Ongoing work in her laboratory seeks to identify novel signal amplifiers (a new class of molecules that she christened GEMs, guanine nucleotide exchange modulators) in a systematic and unbiased way using a three-pronged approach. Using these approaches her laboratory has already identified new rheostats with surprising functions during cellular processes such as membrane-trafficking, autophagy, survival, apoptosis, mitosis, differentiation and migration. Once systematically applied, these approaches have the real potential to revolutionize our understanding of signal transduction and the diverse biological processes and disease states that they control. 

Emergence of a new paradigm: Pradipta's group was one of the original discoverers of this GEM signaling system beginning with the discovery of GIV-GEM, and subsequently extending to 3 other members such as NUCB1/2 and Daple-GEMs. We showed that GEMs serve as vital platforms for intracellular communication networks; they coordinate cellular responses and organellar function in cells responding to environmental signals initiated by diverse classes of receptors, thereby allowing non-GPCRs to engage with and modulate trimeric-GTPases. Using the powerful synergy of cell, molecular and structural-biology, molecular imaging, systems biology and bioinformatics, her group showed the crucial importance of the GEM system in coordinating diverse cellular processes and revealed the mechanistic basis of their GEM action. As a physician-scientist, she relentlessly pursued why/how aberrations in the GEM system spur diseases such as cancer progression, fibrosis and insulin resistance and provided impetus to develop drugs targeting the GEMs in disease states.

This paradigm of intracellular GTPase signaling that is modulated by GEMs is strikingly different from how trimeric-GTPases were previously believed to function in cells. Published and ongoing molecular, structural and systems biology, and molecular imaging studies spearheaded by her lab have confirmed this paradigm and revealed its importance in diseases such as cancers, fibrosis and diabetes. These studies showed that the GEM-GTPase system doesn't just transduce signals; rather, like the Internet communication protocols which link devices worldwide, they serve as network-protocols for intracellular communication at diverse intracellular microdomains. GEMs route signals between organelles and facilitate communication with the cell's exterior.

The leap into the unknown where the findings took: In launching the Center for Network Medicine (CNM), Pradipta's goal is to not only reveal the importance of GEMs in health and diseases, but also unravel other molecules like GEMs that support a complete system of network-protocols for cellular communication; in short, she seeks to decode the Intranet of cells (IoC) using a transdisciplinary approach. The CNM also supports the complete pipeline for network-based target identification and validation through our own Precision Network Medicine initiative, which includes HUMANOID™, a human organoid-based platform. While network-based drug discovery can offer precision in targeting, HUMANOID allows personalized disease-modeling platforms for drug screening. Pradipta's overall vision is to drive disruptive research in biology, medicine and engineering using the fundamentals of the IoC paradigm, with the ultimate goal of enhancing, enriching and improving human existence.

Come discover with us: Pradipta's laboratory has experience and expertise in most cell biological and translational approaches, including live cell imaging, designing and working with FRET probes, protein purification and analysis, protein-protein interaction assays, biochemical and pharmacological assays and in the use of animal models. Pradipta has had a successful training record at UCSD, mentoring several undergraduate, predoctoral students, and postdoctoral associates. 

Pradipta currently devotes ~10% of her time in clinical services. Every Friday morning she either sees patients in a subspeciality outpatient clinic (Hepatology) or performs procedures in endoscopy suits at the VA Medical Center, La Jolla.

Pradipta's Research Mentors:

• (August 2001 - May 2003): Stuart A. Kornfeld, MD
• (September 2006 - November 2008): Marilyn G. Farquhar, PhD

Professional Experience: 

Awards & Honors

Lab Manager
	Nina Sun Email: nnsun@ucsd.edu

Postdoctoral Fellows / Graduate Students
	Ying Dunkel, MD, PhD MD & PhD in Pathology, China Medical University Staff Research Associate, Ghosh Lab (October, 2010-Present) ydunkel@ucsd.edu; yingdunkel@yahoo.com		Cristina Rohena, PhD Doctorate in Cell and Structural Biology (UTHSC at San Antonio) Fellow, Moores Cancer Center. Postdoctoral Fellow (2015-Present) Cancer Therapeutics (CT2) T32 Fellow, Moores Cancer Center  Email: crohena@ucsd.edu
	Jason Ear, PhD Doctorate in Cell and Developmental Biology (University of California, Los Angeles) Postdoctoral Fellow (2015-Present)  Email: jaear@ucsd.edu		Lee Swanson Biomedical Sciences Graduate Student (2015-Present) GI Division T32 Predoctoral Fellow (2015-2018)  Email: laswanso@ucsd.edu
	Nicholas (Nick) Kalogriopoulos Biomedical Sciences Graduate student, Batch of 2013, NCI Cancer Cell Biology Predoctoral Fellow (Aug 2014-July 2016) Email: nkalogri@ucsd.edu Navin Rajapakse, B.Sc, Molecular Biology, SDSU Research Associate (2017 - present) Email: nrakapakse@ucsd.edu		Kwaku (Boadi) Agyekum, PhD PhD in Molecular Biology and Biochemistry/ Cellular Biology and Biophysics,   UMKC. Postdoctoral Fellow, Ghosh Lab (May, 2018- Present) Email: kagyekum@ucsd.edu Yash Mittal, M.D, UCSD School of Medicine; Internal Medicine Residency (Yale), Gastroenterology Fellowship (UCSD).  T32 fellow (2017 - present) Email: Ymittal@ucsd.edu
Undergraduate Student Employees
	Anokhi Saklecha Undergraduate Student, UCSD Student Research Assistant (2015-Present) Intern at University of California, San Diego School of Medicine, United States		Blaze Lim Rachel Liu Pranavi Chhamurthi
	Yogitha Chareddy Undergraduate Student Ghosh Lab (2016-Present)