Stress granules are important for cell survival, forming a protective mechanism for mRNA during periods of stress. Aberrant stress granule function is associated with neurodegenerative diseases in particular the motor neuron disease amyotrophic lateral sclerosis (ALS) and the dementia frontotemporal lobar degeneration (FTLD). Stress granules are a prominent example of a membraneless organelle which is formed, in part, by liquid-liquid phase separation. The fundamental principles by which liquid-liquid phase separation occurs is an area of active investigation. We are investigating the role of nucleic acids in modulating the self-association of RNA binding proteins present in stress granules using biophysical methods. These include the stress granule marker protein, TIA-1 and the prototypical phase separating protein Fused in Sarcoma (FUS) showing the differences in mechanism by which these deceptively similar RNA binding proteins can self-associate with potential implications for stress granule dynamics.