Alex Leo Kolodkin, Ph.D.

Headshot of Alex Leo Kolodkin
  • Deputy Director, Institute for Basic Biomedical Sciences
  • Professor of Neuroscience

Research Interests

Neuronal regeneration; Developmental biology; Cell biology; Neural development more


Dr. Alex Kolodkin is a Professor of Neuroscience at the Johns Hopkins University School of Medicine and Deputy Director of the Institute for Basic Biomedical Sciences. He holds the Charles J. Homcy and Simeon G. Margolis Professorship. His research is focused on understanding how neuronal connectivity is established during development to generate functional circuits.  As a postdoctoral fellow, Dr. Kolodkin discovered the first semaphorin gene in the grasshopper and then determined that semaphorins are a phylogenetically conserved protein family from flies to human. At Hopkins, his laboratory has investigated the roles played by neuronal guidance cues and their receptors in the regulation of neuronal guidance cues and their receptors in the regulation of neuronal morphology and the elaboration of neural connectivity in a wide range of neural systems, both in the fruit fly and in mice. His current work is focused on understanding mammalian visual system development and function, and also on investigating how neural connectivity established in the neocortex.

Dr. Kolodkin received his B.A. in Biology and Religious Studies from Wesleyan University in Middletown CT. He earned his Ph.D. in Molecular Biology and Genetics from the Institute of Molecular Biology at the University of Oregon in Eugene, OR. He completed his postdoctoral fellowship at the University of California, Berkeley. Dr. Kolodkin joined the Johns Hopkins faculty in 1995.

Dr. Kolodkin serves on the editorial board of Neuron and on the review boards of several Federal and Private Foundation funding agencies. His work has been recognized with various awards, including the Javits Neuroscience Investigator Award from the National Institute of Neurological Disorders and Stroke in 2004, the Pradel Research Award of the National Academy of Sciences in 2016, and in 2020 he was elected a Member of the National Academy of Medicine. more


  • Deputy Director, Institute for Basic Biomedical Sciences
  • Charles J. Homcy and Simeon G. Margolis Professor
  • Professor of Neuroscience
  • Joint Appointment in Molecular Biology and Genetics

Departments / Divisions

Centers & Institutes


Additional Training

  • University of California, Berkeley, Berkeley, CA, 1994, Molecular and Cellular Biology

Research & Publications

Research Summary

Alex Kolodkin is a neuroscientist whose laboratory works to understand how neuronal connectivity is established, maintained, and modulated.

His team investigates the function of extrinsic guidance cues and their receptors on axonal guidance, dendritic morphology, and synapse formation and function.

For several years, they've investigated how neural circuits are formed and maintained through the action of guidance cues that include semaphorin proteins, their classical plexin and neuropilin receptors, and also novel receptors. They employ a cross-phylogenetic approach, using both invertebrate and vertebrate model systems, to understand how guidance cues regulate neuronal pathfinding, morphology and synaptogenesis. They also explore how these signals are transduced to cytosolic effectors. Though broad in scope, their interrogation of the roles played by semaphorin guidance cues provides insight into the regulation of neural circuit assembly and function. Their current work includes a relatively new interest in understanding the origins of laminar organization in the CNS. They have identified guidance cues that regulate both specific and general aspects of neurite stratification in the mouse retina, in addition to the targeting of retinal ganglion cell axons to retinorecipient midbrain targets. These observations have prompted them to look for cellular and molecular mechanisms that regulate laminar organization in the mouse neocortex.

Selected Publications

**Peng, Y-R., **James-Esposito, R.E., Yan, W., Kay, J.N., *Kolodkin, A.L. *Sanes, J.R. (2020). Binary fate choice between closely related interneuronal types is determined by a Fezf1-dependent postmitotic transcriptional switch. Neuron, 105, 464-474. [PMCID in progress-NIHMSID:NIHMS1545099] (*co-corresponding authors; **co-first authors)

Xie, X., Tabuchi, M., Corver, A., Duan, G., Wu, M.N., and Kolodkin, A.L. (2019). Semaphorin-2b regulates sleep circuit formation in the Drosophila central brain. Neuron, 104, 322-337. [PMCID: PMC7227428]

Wang, Q., Chiu, S.-L., Koropouli, E., Hong, I., Mitchell, S. P., Easwaran, T.P., Hamilton, N.R., Gustina, A.S., Zhu, Q., Ginty, D.D., Huganir, R.L., and Kolodkin, A.L. (2017). Neuropilin-2/PplexA3 receptors associate with GluA1 and mediate Sema3F-dependent homeostatic scaling in cortical neurons. Neuron, 96, 1084-1098 [PCMID: PMC5726806]

Riccomagno, M.M., Sun, L.O., Brady, C.M., Alexandropoulos, K., Seo, S., Kurokawa, M., and Kolodkin, A.L. (2014).  Cas adaptor proteins organize the retinal ganglion cell layer downstream of integrin signaling. Neuron, 81, 779-786. [PMCID: PMC3988023]

Sun, L.O., Jiang, Z., Rivlin-Etzion, Michal, Hand, R., Brady, C., Matsuoka, R.L., Yau, K.-w., Feller, M.B., and Kolodkin, A.L. (2013). On versus Off direction selective retinal circuits require different Molecular mechanisms for functional assembly (Article). Science, 342,1241947: DOI:10.1126/science.1241974 [PMCID: PMC3863450]

Contact for Research Inquiries

Johns Hopkins University
725 North Wolfe St.
The Solomon H. Snyder Department of Neuroscience
Baltimore, MD 21205 map
Phone: 410-614-9499
Fax: 410-614-8423

Email me

Academic Affiliations & Courses

Graduate Program Affiliation

Neuroscience Graduate Program

Biological Chemistry and Molecular Biology Graduate Program

Cellular and Molecular Medicine Graduate Program

Activities & Honors


  • Elected Member, National Academy of Medicine, 2020
  • Pradel Research Award of the National Academy of Sciences, 2016
  • Elected Fellow of the American Academy of Arts and Sciences, 2016
  • Charles J. Homcy/Simeon G. Margolis Professor, Johns Hopkins University, 2015
  • Elected Fellow, American Association for the Advancement of Science, 2014
  • Howard Hughes Medical Institute Investigator, 2005 – 2018
  • Javits Neuroscience Investigator Award, National Institute of Neurological Disorders and Stroke, 2004
  • National Alliance for Autism Research Award, 2004
  • Kirsch Investigator Award, 2002
  • McKnight Neuroscience Investigator Award, 2000
  • Alfred P. Sloan Research Fellow, 1999
  • Searle Scholars Award, 1996
  • Whitehall Foundation Research Award, 1995
  • McKnight Neuroscience Scholars Award, 1995
  • Klingenstein Fellowship Award in the Neurosciences, 1995

Professional Activities

  • Board of Reviewing Editors, Science, 2014
  • Member, NINDS Board of Scientific Counselors, 2013 - 2018
  • Vice Chair and Chair, Damon Runyon Cancer Fund Fellowship Award Committee, 2011 - 2016
  • Member, NDPR NIH Study Section, 2006 - 2011
  • Associate Editor, Neuron, 2000

Patient Ratings & Comments

The Patient Rating score is an average of all responses to physician related questions on the national CG-CAHPS Medical Practice patient experience survey through Press Ganey. Responses are measured on a scale of 1 to 5, with 5 being the best score. Comments are also gathered from our CG-CAHPS Medical Practice Survey through Press Ganey and displayed in their entirety. Patients are de-identified for confidentiality and patient privacy.

Is this you? Edit Profile
back to top button