Prof. Dr. André Hoelz           

Investigator, Howard Hughes Medical Institute (HHMI)

Mary and Charles Ferkel Professor of Chemistry and Biochemistry

Ph.D. Structural Biology and Biochemistry, The Rockefeller University (2003)

M.Sc. (Diplom) Chemistry and Biochemistry, University of Freiburg, Germany (1997)

B.Sc. (Vordiplom) Chemistry, University of Freiburg, Germany (1993)

hoelz at caltech.edu     CV

Dr. Christopher J. Bley

Research Specialist, Howard Hughes Medical Institute (HHMI)

Lab Manager and Staff Scientist (March 2012 - present)

Safety Officer

Ph.D. Biochemistry, Arizona State University (2011)

M.Sc. Biochemistry, Arizona State University (2008)

B.Sc. Biochemistry and Molecular Biology, University of California, Davis (2004)

cjbley at caltech.edu



Postdoctoral Scholars



Undergraduate Researchers

Back Row: Stefan, George, Raphael, Sabrina, Michael, André, Chris, Vali, Jakub

Front Row: Chia-yu, Denise, Katharina, Michelle, Sema, Ryan, Thomas, Ioana, Narek

Dr. Songhao Zhao

Postdoctoral Scholar (September 2021 - present)

Ph.D. Cell Biology, Institute of Botany, Chinese Academy of Science, China (2020)

M.Eng. Environmental Science and Engineering, Tsinghua University, China (2013)

songhao at caltech.edu

Dr. Stefan Petrovic

Assistant Professor, UCLA

Visiting Associate (December 2024 - present)

Postdoctoral Scholar (June 2022 - November 2024)

Graduate Student (April 2015 - June 2022)

Ph.D Biochemistry and Molecular Biophysics, Caltech (2022)

B.Sc. Cell Biology / Biochemistry, Bucknell University (2014)

Dr. Sema Ejder

Postdoctoral Scholar (July 2021 - present)

Ph.D. Structural Biology and Biochemistry, Newcastle University, UK (2021)

M.Sc. Bioinformatics and Structural Biology, Strasbourg University, France (2017)

B.Sc. Biomedical Sciences, Napier University, UK (2013)

sejder at caltech.edu

Michael Gruhne

Graduate Student (October 2021 - present)

M.Sc. Chemistry, LMU Munich, Germany (2020)

B.Sc. Chemistry and Biochemistry, LMU Munich, Germany (2018)

mgruhne at caltech.edu

Chia Yu Chien

Graduate Student (March 2020 - present)

M.Sc. Plant Biology, National Taiwan University, Taiwan (2014)

B.Sc. Life Science, National Taiwan University, Taiwan (2012)

ccchien at caltech.edu

Dr. Joel Ehrenkranz

Visiting Associate (September 2021 - present)

MD Stanford University School of Medicine (1977)

A.B. Amherst College (1973)

jrle at caltech.edu



High School Researchers

Sofie Wong

High School Student Researcher (July 2023 - present)

High School Senior

Supervised by Chia-Yu Chien

Sabrina Doerrich

Graduate Student (February 2023 - present) *Co-supervised with Alina Patke

Visiting Masters Student (December 2021 - July 2022)

M.Sc. Chemistry, LMU Munich, Germany (2022)

B.Sc. Chemistry and Biochemistry, LMU Munich, Germany (2020)

doerrich at caltech.edu

Mission Statement

The Hoelz group applies interdisciplinary structural cell biology to understand the molecular basis of nucleocytoplasmic transport. We are an internationally diverse community that leverages a broad range of expertise, teamwork, and curiosity to aim for the highest levels of scientific rigor and intellectual excellence. We foster a collegial and inclusive environment that celebrates individual and group successes where knowledge and ideas are freely shared through mentorship and collaboration. Our everyday efforts are dedicated to Caltech’s mission to “expand human knowledge and benefit society through research integrated with education.”

Ryan Delmore

Graduate Student (September 2023 - present)

B.Sc. Biochemistry, California State University, Bakersfield (2023)

US Navy onboard USS Nimitz 2013-2018

rdelmore at caltech.edu

Michelle O’Camb

Administrative Assistant

mocamb at caltech.edu

California Institute of Technology

Division of Chemistry & Chemical Engineering

1200 E. California Blvd.

Pasadena, CA 91125-7200

© Copyright Hoelz Laboratory

Contact Web Manager Last Updated 2/27/2025

Jakub Ettrich

Graduate Student (April 2024 - present)

B.Sc. Chemistry, Biochemistry specialization, Barry University (2023)

jettrich at caltech.edu

Josh Signore

Graduate Student (August 2024 - present) *Co-supervised with Alina Patke

M.A. Chemistry, Wesleyan University (2021)

B.A. Chemistry, Wesleyan University (2019)

jsignore at caltech.edu

Diane Kang

Graduate Student (January 2025 - present)

M.S. Chemistry, University of California Los Angeles (2024)

B.S. Biochemistry, University of California Los Angeles (2023)

dkang3 at caltech.edu



Staff



Graduate Students

Dr. George Mobbs

Staff Scientist (December 2023 - present)

Senior Postdoctoral Scholar (December 2014 - December 2023)

Ph.D. Structural Biology - The University of Sheffield (2014)

M.BiolSci. Biochemistry - The University of Sheffield (2010)

B.Sc. Medical Biochemistry - The University of Sheffield (2009)

gmobbs at caltech.edu

Dr. Narek Yousefian

Postdoctoral Scholar (September 2021 - present)

Double joint Ph.D. Biochemistry, Goethe University Frankfurt, Germany and University of Bordeaux, France (2020)

M.Sc. Biochemisty, University of Bordeaux, France (2016)

B.Sc. Microbiology, Cell and Molecular Biology, University of Pau, France (2014)

narek at caltech.edu

Current Members       Former Members       Former Group Photos

Ioana Caraus

Undergraduate Researcher (March 2024 - present)

Sidney and Nancy Petersen SURF Fellow (2024)

California Institute of Technology, Chemistry Major, Second Year

Supervised by Chia-yu Chien

icaraus at caltech.edu