Deciphering the molecular mechanisms underlying the plasma membrane targeting of PRMT8

Abstract

Arginine methylation plays crucial roles in many cellular functions including signal transduction, RNA transcription, and regulation of gene expression. Protein arginine methyl-transferase 8 (PRMT8), a unique brain-specific protein, is localized to the plasma membrane. However, the detailed molecular mechanisms underlying PRMT8 plasma membrane targeting remain unclear. Here, we demonstrate that the N-terminal 20 amino acids of PRMT8 are sufficient for plasma membrane localization and that oligomerization enhances membrane localization. The basic amino acids, combined with myristoylation within the N-terminal 20 amino acids of PRMT8, are critical for plasma membrane targeting. We also found that substituting Gly-2 with Ala [PRMT8(G2A)] or Cys-9 with Ser [PRMT8(C9S)] induces the formation of punctate structures in the cytosol or patch-like plasma membrane localization, respectively. Impairment of PRMT8 oligomerization/dimerization by C-terminal deletion induces PRMT8 mis-localization to the mitochondria, prevents the formation of punctate structures by PRMT8(G2A), and inhibits PRMT8(C9S) patch-like plasma membrane localization. Overall, these results suggest that oligomerization/dimerization plays several roles in inducing the efficient and specific plasma membrane localization of PRMT8.

The Protein Arginine Methyltransferase PRMT8 and Substrate G3BP1 Control Rac1-PAK1 Signaling and Actin Cytoskeleton for Dendritic Spine Maturation

“…However, the PRMT8-GFP expressed in neurons was not enriched in the nucleus but was more abundant in the cytoplasm and plasma membrane (Figure S1A), which is consistent with a previous study showing a low level of PRMT8 in the nuclear fraction (Penney et al, 2017). To address whether PRMT8 function in spine maturation depends entirely on its action in the nucleus, we generated an RNAi-resistant PRMT8 variant through the addition of a nuclear localization signal (NLS) and the substitution of the second Gly to Ala to disrupt its membrane anchorage (Park et al, 2019). The PRMT8 variant was restricted in the nucleus (Figure S1B), and coexpression of this nuclear PRMT8 failed to rescue the reduction of mushroom In situ hybridization of rat hippocampal neurons (17 DIV), followed by staining of MAP2 (magenta) and nuclear marker DAPI (blue).…”

Forebrain glutamatergic neuron-specific Ctcf deletion induces reactive microgliosis and astrogliosis with neuronal loss in adult mouse hippocampus

“…TUNEL + cells were indicated by green fluorescence. After incubation with DAPI at 1:20,000 dilutions, images of the immunostained sections were acquired with a Zeiss (Thornwood, NY, USA) confocal microscope and an LSM5 EXCITER, version 4.2 ( 25 ). Fluorescence images were analyzed using ImageJ (NIH, Bethesda, MD, USA) and MATLAB (Mathworks, Natick, MA, USA).…”

LIR motifs and the membrane-targeting domain are complementary in the function of RavZ

“…This method has been previously described (21). We cultured HEK293T cells and mouse embryonic fibroblast (MEF) cells in Dulbecco’s modified Eagle’s medium (DMEM) and supplemented with 10% (v/v) fetal bovine serum (FBS) and penicillin/streptomycin in a humidified atmosphere of 5% (v/v) CO 2 at 37°C.…”