TAAR1 levels and sub-cellular distribution are cell line but not breast cancer subtype specific

TAAR1 Expression in Human Macrophages and Brain Tissue: A Potential Novel Facet of MS Neuroinflammation

“…An additional observation arising from our results ( Figure 2 ) is the subcellular protein expression pattern of TAAR1 from the nucleus into the cytoplasm upon pro-inflammatory macrophage stimulation. This finding is consistent with previous results whereby TAAR1 localization is primarily observed within the intracellular environment [ 20 , 24 , 25 , 26 , 27 , 28 ]. Interestingly, there has been no consensus as to the exact location of TAAR1 within the cell.…”

“…In contrast to the common localization of GPCRs within the plasma membrane, reports of TAAR1 expression primarily describe an intracellular localization [ 20 , 24 , 25 , 26 , 27 , 28 ]. Using macrophages derived from human CD14+ peripheral monocytes, we observed TAAR1 localization under standard cell culture conditions and following pro-inflammatory stimulation.…”

“…Nuclear functions of GPCRs are an emerging area of therapeutic interest, with established functions in regulation of transcription, cell proliferation, cell migration, apoptosis, and angiogenesis [ 29 ]. With regards to TAAR1, nuclear sub-cellular distribution has previously been seen in some, but not all, breast cancer cell lines [ 26 ], although the functional relevance of this has yet to be determined. Altered sub-cellular localization of GPCRs has been previously reported to occur during immune cell activation [ 30 ].…”

In focus in HCB

“…Although TAAR1 was detected intracellularly by immunofluorescence in all investigated breast carcinoma cell lines, in some (MCF-7, MDA-MB-468, and SKBR3), it was found to be located in the nucleus. The apparent difference between the results obtained by Pitts et al (2019) and those previously reported by Vattai et al (2017) seems to be due to lack of specificity of the commercially available rabbit anti-TAAR1 antibody, as shown in controls using a rabbit isotype control IgG and by shRNA knockdown.…”

“…Recent data indicated a positive correlation between TAAR1 expression in human breast carcinoma, and both patient survival and HER2 overexpression (Vattai et al 2017), which indicated that TAAR1 might be an independent survival predictor. Extending upon this finding, Pitts et al (2019) have now performed an in-depth bioinformatics analysis of TAAR1 mRNA expression profiles to provide an independent verification of these findings. They report that mRNA expression levels in 20 breast carcinoma cell lines, 6 samples of normal breast tissue, and 31 breast carcinoma samples representing different carcinoma subtypes available within the Gene Expression Omnibus database did not show a correlation with breast carcinoma cell subtype, including HER2 positivity.…”