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Mark A Lemmon, PhD, FRS

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About

Titles

Alfred Gilman Professor and Chair of Pharmacology

Co-director, Cancer Biology Institute

Biography

Mark Lemmon, PhD, FRS is the Alfred Gilman Professor of Pharmacology, and Co-Director of Yale Cancer Biology Institute. He returned to Yale as a named Professor of Pharmacology in 2015 after 19 years on the faculty at the University of Pennsylvania’s Perelman School of Medicine. At Penn, he was the George W. Raiziss Professor of Biochemistry and Biophysics as well as Chair of the department and an Investigator at the Abramson Family Cancer Research Institute. Dr. Lemmon was elected as a Fellow of the Royal Society (the UK's national academy) in 2016, and has been honored with the Dorothy Crowfoot Hodgkin Award of the Protein Society and the Stanley N. Cohen Biomedical Research Award from the University of Pennsylvania. He is on the Editorial Advisory Boards of several journals, including Cell and Molecular Cell, and is Chair of the Editorial Board of the Biochemical Journal.

Dr. Lemmon’s research focuses on understanding the signaling networks controlled by receptor tyrosine kinase (RTK) growth factors that, when mutated, cause cancers and other diseases. His laboratory combines biochemical, structural, biophysical, and cellular approaches to investigate how these networks function, and also collaborates with clinical groups to apply the mechanistic lessons learned to inhibitor choice and combating development of resistance to targeted therapies in the clinic.

Appointments

Education & Training

PhD
Yale University (1993)
BA
Oxford University (Hertford College), Biochemistry (1988)

Research

Overview

Signaling Mechanisms of Receptor Tyrosine Kinases

A major focus of the Lemmon lab is to understand transmembrane signaling by growth factor receptor tyrosine kinases (RTKs), of which there are 58 in the human proteome – separated into 20 different families. Mutations in almost all of these RTKs – some activating, some inactivating – cause cancer or other diseases, and RTKs are important therapeutic targets. We are interested in understanding how these receptors signal, and – importantly – how RTK mutations seen in afflicted patients affect receptor activity. Understanding these mutations provides an important window into molecular mechanism, but also allows us to use our mechanistic understanding to advance development and application of targeted therapeutics. To achieve this, we combine cellular, biochemical, biophysical, and structural approaches – and collaborate closely with geneticists and clinical investigators. Our goal is to link detailed mechanistic understanding to biology in the intact organism (or patient). Although we are interested in all RTKs, and in RTK signaling in general – at the organismal, cellular, and molecular levels (and use a wide variety of approaches) – we are currently focused on the following families (or groups of families) or RTKs:

1. The Epidermal Growth Factor Receptor (EGFR) family
Often considered a ‘prototypic’ RTK, the EGFR has been a major focus of our work for the past decade or so. Combining crystallographic, cellular, and other approaches we have developed a sophisticated understanding of how growth factor binding promotes dimerization of the extracellular region of the receptor, how EGFR is regulated allosterically, and how its intracellular juxtamembrane region contributes to activation. We have also defined the molecular function of the extracellular EGFR inhibitor Argos, from which we hope to extract clues for developing new EGFR inhibitory approaches in cancer.

A second key area in our EGFR work is to understand how different activating ligands can promote distinct modes of signaling through this single receptor. EGF, TGF-alpha, betacellulin, HB-EGF, epiregulin, epigen, and amphiregulin all signal through EGFR - but with subtly different consequences. Our most recent work is revealing some unexpected structural origins for these differences that are impacting how we think about the EGFR. This work is also causing us to appreciate how kinetic aspects of RTK signaling may be very important in defining signaling specificity. We are extending this concept to other receptors, including several involved in immune cell regulation that may be important in immuno-oncology.

2. Understanding activating mutations in RTKs, and how they affect inhibitor response in cancer patients
Working with ALK mutations seen in neuroblastoma patients and EGFR mutations seen in lung cancer patients, we are trying to understand how to define which new mutations seen in patients are activating - in terms of their signaling activity - and how they respond to available ALK or EGFR inhibitors that are being used in the clinic. Working with Ravi Radhakrishnan in Penn Bioengineering, we are also trying to develop algorithms for predicting whether newly identified mutations are activating and inhibitor-sensitive, which we hope will one day guide clinical treatment.

3. RTKs that bind to ligands in the Wnt family
It is now known that several orphan RTKs, namely PTK7/CCK4 (called Lemon in Hydra!), Ror1/2, Ryk, and MuSK are involved in ‘non-canonical’ Wnt signaling. This is a new arena for RTKs, and how they are involved remains unclear. Moreover, PTK7/CCK4, Ror1/2 and Ryk all have so-called pseudokinases in their intracellular region. That is, they look like RTKs, but appear to have ‘dead’ tyrosine kinases. We are working hard to understand how these unusual RTKs mediate signaling by these unexpected ligands, combining biochemical, cellular and structural studies with a collaboration with Peter Klein’s lab at Penn in Xenopus. This work is likely to open new paradigms in RTK signaling and – we hope – to illuminate new therapeutic avenues. We also hope that these studies will shed new light on how pseudokinases function more broadly.

Receptor tyrosine kinases

Medical Subject Headings (MeSH)

Adenocarcinoma; Biochemistry; Cell Membrane; Crystallography; ErbB Receptors; Hydrogen Deuterium Exchange-Mass Spectrometry; MAP Kinase Signaling System; Protein Kinase Inhibitors; Protein Structure, Tertiary; Protein-Tyrosine Kinases; Receptor Aggregation; Signal Transduction; Single Molecule Imaging

Research at a Glance

Yale Co-Authors

Frequent collaborators of Mark A Lemmon's published research.

Publications

2024

2023

2022

Get In Touch

Contacts

Academic Office Number
Secondary Academic Office Number
Mailing Address

Pharmacology

Department of Pharmacology, Yale School of Medicine, B203 Sterling Hall of Medicine

New Haven, CT 06520-8066

United States

Administrative Support

Locations

  • Cancer Biology Institute Office

    Academic Office

    West Campus Advanced Biosciences Center

    840 West Campus Drive, Fl 3, Rm 301

    West Haven, CT 06516

    Appointments

    203.737.7360
  • Medical School Office

    Academic Office

    Sterling Hall of Medicine, B-Wing

    333 Cedar Street, Fl 2, Rm 203

    New Haven, CT 06510

    Appointments

    203.785.6081

Events