PRMT4-mediated arginine methylation negatively regulates retinoblastoma tumor suppressor protein and promotes E2F-1 dissociation.

The retinoblastoma protein (pRb/p105) tumor suppressor plays a pivotal role in cell cycle regulation by blockage of the G1-to-S-phase transition. pRb tumor suppressor activity is governed by a variety of posttranslational modifications, most notably phosphorylation by cyclin-dependent kinase (Cdk) complexes. Here we report a novel regulation of pRb through protein arginine methyltransferase 4 (PRMT4)-mediated arginine methylation, which parallels phosphorylation.

A lytic viral long noncoding RNA modulates the function of a latent protein.

Latent Kaposi's sarcoma-associated herpesvirus (KSHV) episomes are coated with viral latency-associated nuclear antigen (LANA). In contrast, LANA rapidly disassociates from episomes during reactivation. Lytic KSHV expresses polyadenylated nuclear RNA (PAN RNA), a long noncoding RNA (lncRNA).

Kaposi's sarcoma-associated herpesvirus K-Rta exhibits SUMO-targeting ubiquitin ligase (STUbL) like activity and is essential for viral reactivation.

The small ubiquitin-like modifier (SUMO) is a protein that regulates a wide variety of cellular processes by covalent attachment of SUMO moieties to a diverse array of target proteins. Sumoylation also plays an important role in the replication of many viruses. Previously, we showed that Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a SUMO-ligase, K-bZIP, which catalyzes sumoylation of host and viral proteins.

Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen regulates the KSHV epigenome by association with the histone demethylase KDM3A.

Kaposi's sarcoma-associated herpesvirus (KSHV) latent genomes are tethered to host histones to form a minichromosome also known as an "episome." Histones, which are core components of chromatin, are heavily modified by various histone-targeting enzymes. Posttranslational modifications of histones significantly influence accessibility of transcriptional factors and thus have profound effects on gene expression.

KDM8, a H3K36me2 histone demethylase that acts in the cyclin A1 coding region to regulate cancer cell proliferation.

Localized chromatin modifications of histone tails play an important role in regulating gene transcription, and aberration of these processes leads to carcinogenesis. Methylated histone lysine residues, a key player in chromatin remodeling, are demethylated by the JmjC class of enzymes. Here we show that JMJD5 (now renamed KDM8), a JmjC family member, demethylates H3K36me2 and is required for cell cycle progression.