Phoslactomycin targets cysteine‐269 of the protein phosphatase 2A catalytic subunit in cells

Abstract

According to the chemical genetic approach, small molecules that bind directly to proteins are used to analyze protein function, thereby enabling the elucidation of complex mechanisms in mammal cells. Thus, it is very important to identify the molecular targets of compounds that induce a unique phenotype in a target cell. Phoslactomycin A (PLMA) is known to be a potent inhibitor of protein Ser/Thr phosphatase 2A (PP2A); however, the inhibitory mechanism of PP2A by PLMA has not yet been elucidated. Here, we demonstrated that PLMA directly binds to the PP2A catalytic subunit (PP2Ac) in cells by using biotinylated PLMA, and the PLMA-binding site was identified as the Cys-269 residue of PP2Ac. Moreover, we revealed that the Cys-269 contributes to the potent inhibition of PP2Ac activity by PLMA. These results suggest that PLMA is a PP2A-selective inhibitor and is therefore expected to be useful for future investigation of PP2A function in cells.

Total Synthesis and Evaluation of Cytostatin, Its C10−C11 Diastereomers, and Additional Key Analogues: Impact on PP2A Inhibition

“…Although this covalent addition to fostriecin or cytostatin has not been experimentally verified, it was originally supported by the decreased affinity of 2,3-dihydrofostriecin (≥200-fold less potent than 2), 16 and confirmed with the more recent isolation and identification of the analogous Cys269 adduct with phoslactomycin (6). 17 Since the details of the fostriecin-PP2A model have not been disclosed elsewhere, it is presented herein alongside the newly generated cytostatin-PP2A model. Side-by-side overviews of the two models are presented in Figure 11 with space-filling representations of fostriecin and cytostatin.…”

KSRP/FUBP2 Is a Binding Protein of GO-Y086, a Cytotoxic Curcumin Analogue

“…7,8 To determine the molecular target of such protein-reactive small molecules, a pull-down experiment utilizing a biotinylated molecular probe is effective. 9,10 Thus, based on our extensive SAR studies, 11 we designed a biotinylated derivative called GO-Y086, which has the GO-Y016-type substitution pattern (3,3 0 ,4,4 0 ,5,5 0 -hexasubstituted) with a biotin moiety connected at the 4 0 position via a linker.…”

Total Synthesis of Biologically Active Natural Products Based on Highly Selective Synthetic Methodologies

“…In addition, such antagonistic and agonistic compounds also provide useful lead compounds for drug discovery. In this context, we focused on the synthesis of dysiherbaine (37), neodysiherbaine A (38), and kaitocephalin (39). The total syntheses of dysiherbaine (37) and kaitocephalin (39) are presented here.…”

“…In this context, we focused on the synthesis of dysiherbaine (37), neodysiherbaine A (38), and kaitocephalin (39). The total syntheses of dysiherbaine (37) and kaitocephalin (39) are presented here. 57,58) Dysiherbaine (37) was isolated by Sakai et al from the Micronesian sponge Dysidea herbacea and found to be a selective agonist of N-methyl-D-aspartate (NMDA)-type glutamate receptors.…”

“…34) These compounds are highly potent selective inhibitors of protein serine/threonine phosphatase 2A, which is proposed to be responsible for their antitumor activity. [34][35][36][37] Due to their intriguing molecular architectures and potential as lead compounds for anticancer drugs as well as their importance as a biological tool, this family of compounds has attracted much attention in the chemical and biological research communities. Thus, there have been a number of synthetic studies including formal and total syntheses of phoslactomycin A 38) and B, [39][40][41][42] leustroducsin B, [43][44][45][46][47] fostriecin, [47][48][49] and PD113,271.…”