Investigating the localization and function of the prodomain of Neuronal interleukin-16 on N1E-115 cells

Cassondra Agozzino, The College of Wooster

Abstract

Neuronal interleukin-16 (NIL-16) is a neuronal protein and is one of the two isoforms of the pro-IL-16 gene. While little is known about the function of NIL-16 in the nervous system, the smaller isoform, pro-interleukin-16 (pro-IL-16), is known to control the cell cycle in T-lymphocytes of the immune system. In addition, pro-IL-16 serves as a precursor protein for the secreted cytokine interleukin-16 (IL-16), which induces a variety of cellular responses connected with the immune system. The prodomain of pro-IL-16 contains a nuclear localization signal (NLS) that allows for translocation to the nucleus. NIL-16 shares the same NLS as pro-IL-16, and thus it is hypothesized that the prodomain of NIL-16 may similarly translocate to the nucleus. This was tested by transfecting GFP and FLAG-tag N-terminal fusion constructs of full-length NIL-16 and the prodomain of NIL-16 into N1E-115 neuroblastoma cells and then visualizing the subcellular localization of these constructs. The localization of the constructs was scored as either cytosolic or nucleic. The results showed no significant differences between the localization of full-length NIL-16 or its prodomain. Collectively, these findings suggest that the prodomain of NIL-16 does not translocate to the nucleus in N1E-115 cells under the conditions tested.