Caveolin‐1 down‐regulation is required for Wnt5a‐Frizzled 2 signalling in Ha‐RasV12‐induced cell transformation

Caveolin‐1 (Cav1) is down‐regulated during MK4 (MDCK cells harbouring inducible Ha‐Ras^V12 gene) transformation by Ha‐Ras^V12. Cav1 overexpression abrogates the Ha‐Ras^V12‐driven transformation of MK4 cells; however, the targeted down‐regulation of Cav1 is not sufficient to mimic this transformation. Cav1‐silenced cells, including MK4/shCav1 cells and MDCK/shCav1 cells, showed an increased cell area and discontinuous junction‐related proteins staining. Cellular and mechanical transformations were completed when MDCK/shCav1 cells were treated with medium conditioned by MK4 cells treated with IPTG (MK4+I‐CM) but not with medium conditioned by MK4 cells. Nanoparticle tracking analysis showed that Ha‐Ras^V12‐inducing MK4 cells increased exosome‐like microvesicles release compared with their normal counterparts. The cellular and mechanical transformation activities of MK4+I‐CM were abolished after heat treatment and exosome depletion and were copied by exosomes derived from MK4+I‐CM (MK4+I‐EXs). Wnt5a, a downstream product of Ha‐Ras^V12, was markedly secreted by MK4+I‐CM and MK4+I‐EXs. Suppression of Wnt5a expression and secretion using the porcupine inhibitor C59 or Wnt5a siRNA inhibited the Ha‐Ras^V12‐ and MK4+I‐CM‐induced transformation of MK4 cells and MDCK/shCav1 cells, respectively. Cav1 down‐regulation, either by Ha‐Ras^V12 or targeted shRNA, increased frizzled‐2 (Fzd2) protein levels without affecting its mRNA levels, suggesting a novel role of Cav1 in negatively regulating Fzd2 expression. Additionally, silencing Cav1 facilitated the internalization of MK4+I‐EXs in MDCK cells. These data suggest that Cav1‐dependent repression of Fzd2 and exosome uptake is potentially relevant to its antitransformation activity, which hinders the activation of Ha‐Ras^V12‐Wnt5a‐Stat3 pathway. Altogether, these results suggest that both decreasing Cav1 and increasing exosomal Wnt5a must be implemented during Ha‐Ras^V12‐driven cell transformation.     

Reversed Hyperbolic Plasmonic Responses in Phosphorene Under Uniaxial Strain

In this paper, hyperbolic plasmonic responses of phosphorene under uniaxial strains have been explored within density functional theory. In the hyperbolic regime, plasmonic slab waveguide modes are found only along armchair direction. Then, uniaxial strains up to 10% have been applied along zigzag and armchair directions, which can significantly modify its plasmonic responses. Under appropriate strain, the signs of permittivities along two in-plane directions can be even reversed, causing switching of the propagating direction of the plasmonic modes into zigzag direction. Our investigations may give a general idea about how to control the hyperbolic plasmonic modes in phosphorene via strain.

     

Correction to: Microhabitats of sharknose goby (Elacatinus evelynae) cleaning stations and their links with cleaning behaviour

Coral Reefs - A correction to this paper has been published: https://doi.org/10.1007/s00338-021-02111-z     

江苏菜豆同工凝集素的分离纯化及性质研究

江苏菜豆经酸水(PH2.0)抽提,硫酸铵分级沉淀,分离植物血球凝集素(PHA-P),分子量为128000的糖蛋白,活性回收率在80％以上,PHA-P经SP-sephadexc-50离子交换层析,分成L_4,L_3E_1,L_2E_2,L_1E_3,和E_4同工凝集素。 L_4和E_4等电点为5.4和6.5。亚基分子量分别是31000和33000,并有类似的氨基酸组成。PAGE分析为单一蛋白带。红细胞凝集活性随电泳迁移速度的加快而增强,促淋性细胞分裂活性则减弱。E_4血凝活性受CalNAc,EDTA抑制和Zn~(++)的促进。     

The amino acid sequence of peanut agglutinin

The amino acid sequence of peanut (Arachis hypogaea) agglutinin was determined from three major fragments obtained by mild acid cleavage at Asp-Pro peptide bonds. The sequence of 236 amino acids has residues identical to those that form the metal-binding site and the hydrophobic pocket in concanavalin A and other lectins, although the overall similarity is only 42%. In the segments of peanut agglutinin that correspond to the four loops that form the carbohydrate-binding site in concanavalin A and favin, several central residues are homologous, while others show changes to smaller side chains, such as Tyr----Gly. The carbohydrate-binding site of peanut agglutinin may therefore have a similar peptide-backbone architecture, but form a considerably more open cleft.