Fig. 3: A CK2-βTrCP axis regulates SUN1/2 degradation to mediate LPS-induced remodeling of the nucleus in macrophages.
From: SUN1/2 controls macrophage polarization via modulating nuclear size and stiffness
a Protein levels of SUN1/2 in LPS-stimulated PEMs after being treated with MG132. b Ubiquitination of SUN2 in PEMs upon LPS stimulation. c Immunoblotting analysis of SUN1/2 in βTrCP1/2-knockdown 293 T cells after being treated with MG132. d Ubiquitination of SUN2 after transfection of 293 T cells with βTrCP. e Ubiquitination of wildtype SUN2 and its SA mutant in which the βTrCP-binding motif was disrupted. WT, wildtype; SA, SUN2 (S131A/S132A/S136A). f The average size of the nucleus of THP-1-derived macrophages stably expressing the SUN2 SA mutant. e.v., empty vector; SA, SUN2 (S131A/S132A/S136A), same below. g AFM images of nuclei from HEK293FT cells after transfection with SUN (WT) or the SUN2 SA mutant (n = 18 nuclei per group). Scale bar, 5 μm. h Immunoblotting of SUN1/2 in LPS-stimulated macrophages after being treated with TBB, a CK2 inhibitor. i In vitro kinase assay for CK2 using purified recombinant proteins of SUN2 (WT) and SUN2 (SA) as substrates. j Average size of THP-1-derived macrophage nuclei after treatment with TBB. k AFM images of nuclei from THP-1-derived macrophages treated with TBB (n = 18 nuclei per group). Scale bar, 5 μm. l Average size of SUN1/2 (WT) and Sun1/2DKO PEMs nuclei after treatment with LPS. m Mechanical properties of nuclei in SUN1/2 (WT) and Sun1/2DKO MEFs after treatment with LPS (n = 33 nuclei per group). Scale bar, 5 μm. Representative of 2 independent experiments (a–e, h, i). Data were presented as means ± SD (f, j, k). Two-sided unpaired student’s t test was used to compare difference between two groups (f, j, k). *p < 0.05; **p < 0.01; ***p < 0.001, n.s. no significance (p > 0.05) in comparison with control group. See also Supplementary Fig. 3.
