Tracy Tran

Tracy Tran


tstran [at]



Office Location

601D Life Sciences Center


Understanding the mechanisms that govern neuronal wiring is a central focus of developmental neurobiology and, importantly, will result in the identification of molecular mechanisms relevant in many disease processes. The overarching goal of our research is to better understand how molecular cues regulate neuronal morphogenesis, synapse development and refinement, which lead to the proper wiring of the nervous system that ultimately result in the execution of complex behavior in the organism. 

Accordingly, our research team is interested in the following questions: 1) what are the molecules controlling neural circuit formation? 2) how are these connections maintained throughout life? and 3) what are the underlying cellular mechanisms controlling axonal guidance versus synapse formation? To address these questions, we will employ cellular, molecular, and genetic approaches to analyze both the central and peripheral arms of the mouse nervous system. We will use a combination of interdisciplinary approaches including, but not limited to, sophisticated mouse genetics (inducible knockout/knockin, CRISPR) to perform in vitro and in vivo experiments, and physiology and behavioral analysis to provide a platform to study complex neural circuit functions and how defects in salient connections may lead to the development of neurological disorders, such as autism spectrum disorder. 

Courses Taught

Recently taught courses:

2022 (fall): New Course - Cellular Neurobiology (26:120:589, Grad); Co-course director.

2016 - present (spring): Introduction to Neuroanatomy: Structure and Function (21:120:404, Undergrad); Course Director.

2017 - present (fall, spring, summer): Problems in Biology (21:120:491 and 492, Undergrad Research); Course Director.

2019 & 2021 (fall): Topics in Biology: Neurodevelopment (26:120:616, Grad); Course Director.


B.S. in Physiological Sciences/Neuroscience, University of California, Los Angeles, degree conferred 1998.
Ph.D. in Molecular, Cellular and Integrative Physiology, University of California, Los Angeles, degree conferred 2003.

Postdoctoral Training:

National Institutes of Health (NIH), NINDS, Neurogenetics Branch, 2003-2004.

Johns Hopkins University School of Medicine, The Solomon H. Snyder Department of Neuroscience, 2004-2010.


Selected Publications:

(See complete Bibliography here:

Khdour HY, Kondabolu K, Khadka A, Assous M, Tepper J, Tran TS, Polack PO. Neuropilin 2/Plexin-A3 Receptors Regulate the Functional Connectivity and the Excitability in the Layers 4 and 5 of the Cerebral Cortex. J Neurosci. 2022 May 9;. doi: 10.1523/JNEUROSCI.1965-21.2022. [Epub ahead of print] PubMed PMID: 35534225.

Szczurkowska J, Guo A, Martin J, Lee SI, Martinez E, Chien CT, Khan TA, Singh R, Dadson D, Tran TS, Pautot S, Shelly M. Semaphorin3A/PlexinA3 association with the Scribble scaffold for cGMP increase is required for apical dendrite development. Cell Rep. 2022 Mar 15;38(11):110483. doi: 10.1016/j.celrep.2022.110483. PubMed PMID: 35294878; PubMed Central PMCID: PMC8994670.

Eisenberg C, Subramanian D, Afrasiabi M, Ziobro P, DeLucia J, Hirschberg PR, Shiflett MW, Santhakumar V, Tran TS. Reduced hippocampal inhibition and enhanced autism-epilepsy comorbidity in mice lacking neuropilin 2. Transl Psychiatry. 2021 Oct 18;11(1):537. doi: 10.1038/s41398-021-01655-6. PubMed PMID: 34663783; PubMed Central PMCID: PMC8523694.

Danelon, V, Goldner, R, Martinez, E, Gokhman, I, Wang, K, Yaron, A, Tran, TS. (2020). Modular and distinct Plexin-A4/FARP2/Rac1 signaling controls dendrite morphogenesis. J. Neurosci. 40:5413-5430. DOI: (Cover Article)

Assous, M, Martinez, E, Eisenberg, C, Shah, F, Kosc, A, Varghese, K, Espinoza, D, Bhimani, S, Tepper, JM, Shiflett, MW, Tran, TS. (2019). Neuropilin 2 Signaling Mediates Corticostriatal Transmission, Spine Maintenance, and Goal-Directed Learning in Mice. J Neurosci. 39:8845-8859. doi: 10.1523/JNEUROSCI.1006-19.2019.

Kung F, Wang, W, Tran, TS, Townes-Anderson, E. (2017). Sema3A Reduces Sprouting of Adult Rod Photoreceptors In Vitro. Invest Opthalmol Vis Sci. 58:4318-433`. doi: 10.1167/iovs.16-21075.

Shiflett, MW, Martinez, E, Khdour, H, Tran, TS. (2017). Functions of Neuropilins in Wiring the Nervous System and Their Role in Neurological Disorders. In: The Neuropilins: Role and Function in Health and Disease. Neufeld G, Kessler O, editors. Switzerland: Springer Nature; Chapter 8; p.125-149.

Peng, SS, Tran, TS. (2017). Regulation of Cortical Dendrite Morphology and Spine Organization by Secreted Semaphorins: A Primary Culture Approach. Methods Mol Biol. 1493:209-222. doi: 10.1007/978-1-4939-6448-2_15.

Hernandez-Enriquez, B, Wu, Z, Martinez, E, Olsen, O, Kaprielian, Z, Maness, PF, Yoshida, Y, Tessier-Lavigne, M, Tran, TS. (2015). Floor plate-derived neuropilin-2 functions as a secreted semaphorin sink to facilitate commissural axon midline crossing. Genes Dev. 29:2617-2632. doi: 10.1101/gad.268086.115.

Martinez, E, Tran, TS. (2015). Vertebrate spinal commissural neurons: a model system for studying axon guidance beyond the midline. Wiley Interdiscip Rev Dev Biol. 4:283-297. doi: 10.1002/wdev.173.

Shiflett, MW, Gavin, M, Tran, TS. (2015). Altered hippocampal-dependent memory and motor function in neuropilin 2-deficient mice. Transl Psychiatry. 5:e521. doi: 10.1038/tp.2015.17.

Yu, S, Yehia, G, Wang, J, Stypulkowski, E, Sakamori, R, Jiang, P, Hernandez-Enriquez, B, Tran, TS, Bonder, EM, Guo, W, Gao, N. (2014). Global ablation of the mouse Rab11a gene impairs early embryogenesis and matrix metalloproteinase secretion. J Biol Chem. 289:32030-32043. doi: 10.1074/jbc.M113.538223.

Demyanenko, GP, Mohan, V, Zhang, X, Brennaman, LH, Dharbal, KE, Tran, TS, Manis, PB, Maness, PF. (2014). Neural cell adhesion molecule NrCAM regulates Semaphorin 3F-induced dendritic spine remodeling. J Neurosci. 34:11274-11287. doi: 10.1523/JNEUROSCI.1774-14.2014.

Mlechkovich, G, Peng, SS, Shacham, V, Martinez, E, Gokhaman, I, Minis, A, *Tran, TS, *Yaron, A. (2014). Distinct cytoplasmic domains in Plexin-A4 mediate diverse responses to semaphorin 3A in developing mammalian neurons. Sci. Signal. 7:ra24. doi: 10.1126/scisignal.2004734. (*co-corresponding authors)

*#Tran, TS, *Carlin, E, Lin, R, Martinez, E, Johnson, JE, #Kaprielian, Z. (2013). Neuropilin 2 regulates the guidance of post-crossing spinal commissural axons in a subtype-specific manner. Neural Dev. 8:15. doi: 10.1186/1749-8104-8-15. (*co-first and #co-corresponding authors)

Calderon de Anda, F, Rosario, AL, Durak, O, Tran, T, Graff, J, Meletis, K, Rei, D, Soda, T, Madabhushi, R, Ginty, DD, Kolodkin, AL, Tsai, L. (2012).  Autism spectrum disorder susceptibility gene TAOK2 affects basal dendrite formation in the neocortex.  Nat. Neurosci. 15: 1022-31. doi: 10.1038/nn.3141.

Becker, PM, Tran, TS, Delannoy, MJ, He, CX, Shannon, JM, McGrath-Morrow, S. (2011). Semaphorin 3A contributes to distal pulmonary epithelial cell differentiation and lung morphogenesis.  PLoS One 6. doi: 10.1371/journal.pone.0027449.

Demyanenko, GP, Riday, TT, Tran, TS, Dalal, J, Darnell, EP, Brennaman, LH, Sakurai, T, Grumet, M, Philpot, BD, Maness, PF. (2011). NrCAM deletion causes topographic mistargeting of thalamocortical axons to the visual cortex and disrupts visual acuity. J. Neurosci. 31:1545-1558. doi: 10.1523/JNEUROSCI.4467-10.2011.

Tran, TS, Rubio, ME, Clem, RL, Johnson, D, Case, L, Tessier-Lavigne, M, Huganir, RL, Ginty, DD and Kolodkin, AL. (2009). Secreted semaphorins control spine distribution and morphogenesis in the postnatal CNS. Nature, 462:1065-1069. doi: 10.1038/nature08628.

Kolk, SM, Gunput, RF, Tran, TS, van den Heuvel, DMA, Prasad, AA, Hellemons, AJGM, Adolfs, Y, Ginty, DD, Kolodkin, AL, Burbach, PH, Smidt, MP, Pasterkamp, RJ. (2009). Semaphorin 3F is a bifunctional guidance cue for dopaminergic axons and controls their fasciculation, channeling, rostral growth and intracortical targeting. J. Neurosci. 29:12542-12557. doi: 10.1523/JNEUROSCI.2521-09.2009.

Wright, AG, Demyanenko, GP, Powell, A, Schachner, M, Enriquez-Barreto L, Tran, TS, Polleux, F, and Maness, PF. (2007). Close Homolog of L1 and Neuropilin 1 mediate guidance of thalamocortical axons at the ventral telencephalon. J. Neurosci. 27:13667- 13679. doi: 10.1523/JNEUROSCI.2888-07.2007.

Tran, TS, Kolodkin, AL, and Bharadwaj, R. (2007). Semaphorin regulation of cellular morphology. Ann. Rev. Cell Dev. Biol. 23:263-292. doi: 10.1146/annurev.cellbio.22.010605.093554.

Hoe, H-S, Tran, TS, Matsuoka, Y, Howell, BW and Rebeck, GW. (2006). DAB1 and Reelin effects on amyloid precursor protein and ApoE receptor 2 trafficking and processing. J. Biol. Chem. 281:35176-35185. doi: 10.1074/jbc.M602162200.

Huber, AB, Kania, A, Tran, TS, Gu, C, De Marco Garcia, N, Lieberam, I, Johnson, D, Jessell, TM, Ginty, DD and Kolodkin, AL. (2005). Distinct roles for secreted semaphorin signaling in spinal motor axon guidance. Neuron, 48:949-964. doi: 10.106/j.neuron.2005.12.003.

Associated Programs

Faculty advisor for majors in:

Clinical Laboratory Sciences

Medical Imaging Sciences