c-Src kinase is involved in the tyrosine phosphorylation and activity of SLC11A1 in differentiating macrophages

Abstract

Studies have demonstrated that the solute carrier family 11 member 1 (SLC11A1) is heavily glycosylated and phosphorylated in macrophages. However, the mechanisms of SLC11A1 phosphorylation, and the effects of phosphorylation on SLC11A1 activity remain largely unknown. Here, the tyrosine phosphorylation of SLC11A1 is observed in SLC11A1-expressing U937 cells when differentiated into macrophages by phorbol myristate acetate (PMA). The phosphorylation of SLC11A1 is almost completely blocked by treatment with PP2, a selective inhibitor of Src family kinases. Furthermore, we found that SLC11A1 is a direct substrate for active c-Src kinase and siRNA-mediated knockdown of cellular Src (c-Src) expression results in a significant decrease in tyrosine phosphorylation. We found that PMA induces the interaction of SLC11A1 with c-Src kinase. We demonstrated that SLC11A1 is phosphorylated by Src family kinases at tyrosine 15 and this type of phosphorylation is required for SLC11A1-mediated modulation of NF-κB activation and nitric oxide (NO) production induced by LPS. Our results demonstrate important roles for c-Src tyrosine kinase in phosphorylation and activation of SLC11A1 in macrophages.

FER-mediated tyrosine phosphorylation and PIK3R2/p85β recruitment on IRS4 promotes the PI3K-AKT signaling pathway and tumorigenesis in ovarian cancer

“…SLC3A2, ATP1A1 and ATP2A2 ( Fig 1C). Notably, tyrosine phosphorylation has been reported as an important layer of regulation for transporter proteins' stability (45) and activity (46)(47)(48)(49). We also identified CTLC (Clathrin Heavy Chain) and COPA (COPI Coat Complex Subunit Alpha) as potential FER associated proteins, the functions of which are involved in both Clathrin-dependent and -independent intracellular trafficking ( Fig 1C).…”

Extracellular Vesicle Activation of Latent HIV-1 Is Driven by EV-Associated c-Src and Cellular SRC-1 via the PI3K/AKT/mTOR Pathway

“…EVs from CEM, Jurkat, and U937 cell lines were then concentrated using Nanotraps (NT80/82) and Western blotted for the presence of phosphorylated c-Src (Y416), total c-Src, and actin. An antibody against phosphorylated c-Src (Y416) was used, since when c-Src is phosphorylated at Y416, it is catalytically active and able to phosphorylate downstream proteins such as EGFR [ 43 , 44 ]. The data in Figure 1 C show that EVs from T cells (CEM and Jurkat) and monocyte/myeloids (U937) do indeed contain phosphorylated c-Src (Y416).…”

“…Furthermore, this c-Src was observed to be phosphorylated at tyrosine-416 ( Figure 1 C). This indicates that EV-associated c-Src could be enzymatically active as phosphorylation at tyrosine-416 has been shown to be associated with activated c-Src, which can phosphorylate downstream targets [ 43 , 44 ]. Among these targets are EGFR [ 46 ] and histone H1 [ 45 ].…”

FER-mediated phosphorylation and PIK3R2 recruitment on IRS4 promotes AKT activation and tumorigenesis in ovarian cancer cells

“…Besides IRS4 and IGF1R ( Stanicka et al, 2018 ), our mass spectrometry analysis captured several interesting FER-interacting hits with functions of solute transportation, including SLC25A5 , SLC25A6 SLC3A2 , ATP1A1, and ATP2A2 ( Figure 1C ). Notably, tyrosine phosphorylation has been reported as an important layer of regulation for transporter proteins’ stability ( Loureiro et al, 2019 ) and activity ( Xu et al, 2018 ; Zhao et al, 2016 ; Hedges et al, 2013 ; Wertheimer et al, 2008 ). We also identified CTLC (Clathrin Heavy Chain) and COPA (COPI Coat Complex Subunit Alpha) as potential FER-associated proteins, the functions of which are involved in both Clathrin-dependent and -independent intracellular trafficking ( Figure 1C ).…”