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Karl Willert, PhD

Associate Professor, Cellular & Molecular Medicine
Director, Human Embryonic Stem Cell Core Facility, Stem Cell Program

Contact Information

Office: 858-822-3235
Lab: 858-534-9326
Fax: 858-246-1579

Sanford Consortium for Regenerative Medicine
2880 Torrey Pines Scenic Drive, Room 3009
La Jolla, CA 92037

Lab Website

Dr. Karl Willert is an expert in stem cell and developmental biology. Dr. Willert obtained a Bachelor of Science in Biochemistry from the University of California, San Diego (1989) and earned a Ph.D. in Biochemistry  (1996) from the University of California, San Francisco under the guidance of Dr. Harold Varmus.  Subsequently, he worked as a post-doctoral fellow with Dr. Roeland Nusse at Stanford University in Palo Alto, California. In 2008, after working in the biotechnology sector for a few years, Dr. Willert was recruited as an Assistant Professor in the Department of Cellular & Molecular Medicine at the University of California, San Diego.

Underlying Dr. Willert’s research interests has been the study of WNT proteins, a family of secreted growth factors that regulate embryonic development and tissue homeostasis and impact a large number of human diseases, including neurodegeneration and cancer. Throughout his scientific career, Dr. Willert has incorporated biochemical, genetic and cell biological approaches to study these proteins and their signaling cascades. In a seminal study, Dr. Willert purified WNT proteins (he holds the patent on the “Composition of Active WNT protein”) and demonstrated that they harbor potent stem cell growth factor activities. His current research focuses on how WNT proteins regulate self renewal and differentiation of human pluripotent stem cells. He is actively collaborating on multiple projects, including with colleagues Dr. Dennis Carson (WNT-FZD signaling in cancer), Dr. Terry Gaasterland (genome-wide approaches to understanding WNT signaling), Dr. Maike Sander (generation of human pancreatic beta cells), Dr. David Traver (specification of hematopoietic stem cells), and Dr. Gene Yeo (integration of WNT signaling and RNA binding proteins).

Dr. Willert has authored over 40 peer-reviewed publications, invited book chapters and review articles in the areas of WNT biochemistry and signaling and stem cell biology. Dr. Willert has been awarded 3 grants from the California Institute of Regenerative Medicine totaling $7.1 million.  His research is also supported by The National Institute of Health and the National Foundation for Ectodermal Dysplasias. 


Research Focus Areas:

Developmental Biology  |  Signal Transduction  |  Stem Cell Biology


Dr. Willert's Publications (PubMed)


Selected Publications:

Fernandez, A., Huggins, I. J., Perna, L., Brafman, D., Lu, D., Yao, S., Gaasterland, T., Carson, D., Willert K. The WNT receptor FZD7 is required for maintenance of the pluripotent state in human embryonic stem cells. Proc Natl Acad Sci U S A, 111:1409-14 (2014). PMID: 24474766

Brafman, D., Moya, N., Soltero, S., Fellner, T., Robinson, M., Vomberg-McMillen, Z., Gaasterland, T., Willert, K. Analysis of SOX2 expressing cell populations derived from human pluripotent stem cells. Stem Cell Reports, 1: 464-78 (2013). PMID: 24286033, PMC3841266

Brafman, D., Chien, S., Willert, K.  Arrayed cellular microenvironments for identifying culture and differentiation conditions for stem, primary and rare cell populations. Nature Protocols 7, 703-17 (2012). PMID: 22422316

Willert, K., Nusse, R. WNT proteins. Cold Spring Harb Perspect Biol, doi: 10.1101/cshperspect.a007864 (2012). PMID: 22952392

Bauer, M., Bénard, J., Gaasterland, T., Willert, K.*, Cappellen, D.*. WNT5A encodes two isoforms with distinct functions in cancers. PLoS ONE, 8:e80526 (2013). (* corresponding authors) PMID: 242460510

Brafman, D., Kumar, N., Phung, C., Willert, K. Regulation of endodermal differentiation of human embryonic stem cells through integrin-ECM interactions. Cell Death and Differentiation, doi:10.1038/cdd.2012.138 (2013). PMID: 23154389, PMC3569984

Willert, K., Brown J., Danenberg E., Duncan A., Weissman I.L., Reya T., Yates III J.R., and Nusse R. Wnt proteins are lipid-modified and can act as stem cell factors. Nature 423, 448-452 (2003). PMID:12717451