Fig 2: BAG3 interacts with synaptic vesicle proteins and synapsins likely via the WW domain.a Co-immunoprecipitation with Syn antibody and probing for BAG3 confirms the interaction of BAG3 with synapsins in rat primary cortical and hippocampal neurons under normal and oxidative stress conditions. b Co-immunoprecipitation with BAG3 antibody and probing for synaptotagmin 1 confirms the interaction of BAG3 and Syt1. c BAG3 co localizes with Syt1 in neurons. d, e Expression of Flag-BAG3 (1–300) in neurons results in the disruption of neuronal synapsins distribution similar to BAG3 KD and Tat expression

Fig 3: HIV-1 Tat promotes alterations in synaptic vesicle proteins distribution and homeostasis.a Single neuron images showing that Tat overexpression affects neuronal processes and synaptic vesicle distribution as stained with Tubb3 and synapsins (Syn), respectively. Synapsins accumulate close to soma upon Tat expression, compared to the control where synapsins are primarily observed in neuronal processes. b Synapsin distribution in neurons in a population wide image shows the disruption of synaptic vesicle network during Tat expression. c A second synaptic vesicle marker, synaptotagmin 1 (Syt1), confirms the aggregation of synaptic vesicle proteins in neurons upon Tat expression as compared to the Ad-Null transduction. d In addition to distribution, total synapsin proteins levels are altered in the soluble and insoluble fractions of neuronal lysate upon Tat expression. e Synaptotagmin 1 exhibits more accumulation in the insoluble fraction compared to soluble fraction (~70%) in neurons where Tat is expressed. f Dose response of soluble recombinant Tat (rTat) protein on the distribution of synapsins indicates the increased impairment at higher doses of Tat. Syt1, Syn, and Tubb3 stand for synaptotagmin 1, synapsins, and ß3-tubulin, respectively