Stepwise release of Activin-A from its inhibitory prodomain is modulated by cysteines and requires furin coexpression to promote melanoma growth.

The Activin-A precursor dimer can be cleaved by furin, but how this proteolytic maturation is regulated in vivo and how it facilitates access to signaling receptors is unclear. Here, analysis in a syngeneic melanoma grafting model shows that without furin coexpression, Activin-A failed to accelerate tumor growth, correlating with failure of one or both subunits to undergo cleavage in signal-sending cells, even though compensatory processing by host cells nonetheless sustained elevated circulating Activin-A levels. In reporter assays, furin-independent cleavage of one subunit enabled juxtacrine Activin-A signaling, whereas completion of proteolytic maturation by coexpressed furin or by recipient cells stimulated contact-independent activity, crosstalk with BMP receptors, and signal inhibition by follistatin.

Antagonistic interactions among structured domains in the multivalent Bicc1-ANKS3-ANKS6 protein network govern phase transitioning of target mRNAs.

The growing number of diseases linked to aberrant phase transitioning of ribonucleoproteins highlights the need to uncover how the interplay between multivalent protein and RNA interactions is regulated. Cytoplasmic granules of the RNA binding protein Bicaudal-C (Bicc1) are regulated by the ciliopathy proteins ankyrin (ANK) and sterile alpha motif (SAM) domain-containing ANKS3 and ANKS6, but whether and how target mRNAs are affected is unknown. Here, we show that head-to-tail polymers of Bicc1 nucleated by its SAM domain are interconnected by K homology (KH) domains in a protein meshwork that mediates liquid-to-gel transitioning of client transcripts.

Volatile emission and biosynthesis in endophytic fungi colonizing black poplar leaves.

Plant volatiles play a major role in plant-insect interactions as defense compounds or attractants for insect herbivores. Recent studies have shown that endophytic fungi are also able to produce volatiles and this raises the question of whether these fungal volatiles influence plant-insect interactions. Here, we qualitatively investigated the volatiles released from 13 endophytic fungal species isolated from leaves of mature black poplar () trees.

The box C/D snoRNP assembly factor Bcd1 interacts with the histone chaperone Rtt106 and controls its transcription dependent activity.

Biogenesis of eukaryotic box C/D small nucleolar ribonucleoproteins initiates co-transcriptionally and requires the action of the assembly machinery including the Hsp90/R2TP complex, the Rsa1p:Hit1p heterodimer and the Bcd1 protein. We present genetic interactions between the Rsa1p-encoding gene and genes involved in chromatin organization including RTT106 that codes for the H3-H4 histone chaperone Rtt106p controlling H3K56ac deposition. We show that Bcd1p binds Rtt106p and controls its transcription-dependent recruitment by reducing its association with RNA polymerase II, modulating H3K56ac levels at gene body.

Role of the RNA-binding protein Bicaudal-C1 and interacting factors in cystic kidney diseases.

Polycystic kidneys frequently associate with mutations in individual components of cilia, basal bodies or centriolar satellites that perturb complex protein networks. In this review, we focus on the RNA-binding protein Bicaudal-C1 (BICC1) which was found mutated in renal cystic dysplasia, and on its interactions with the ankyrin repeat and sterile α motif (SAM)-containing proteins ANKS3 and ANKS6 and associated kinases and their partially overlapping ciliopathy phenotypes. After reviewing BICC1 homologs in model organisms and their functions in mRNA and cell metabolism during development and in renal tubules, we discuss recent insights from cell-based assays and from structure analysis of the SAM domains, and how SAM domain oligomerization might influence multivalent higher order complexes that are implicated in ciliary signal transduction.

FAM19A4/miR124-2 methylation in invasive cervical cancer: A retrospective cross-sectional worldwide study.

Widespread adoption of primary human papillomavirus (HPV)-based screening has encouraged the search for a triage test which retains high sensitivity for the detection of cervical cancer and precancer, but increases specificity to avoid overtreatment. Methylation analysis of FAM19A4 and miR124-2 genes has shown promise for the triage of high-risk (hr) HPV-positive women. In our study, we assessed the consistency of FAM19A4/miR124-2 methylation analysis in the detection of cervical cancer in a series of 519 invasive cervical carcinomas (n = 314 cervical scrapes, n = 205 tissue specimens) from over 25 countries, using a quantitative methylation-specific PCR (qMSP)-based assay (QIAsure Methylation Test®).

Reduction of cervical cancer incidence within a primary HPV screening pilot project (WOLPHSCREEN) in Wolfsburg, Germany.

Background: Randomised controlled trials showed human papillomavirus (HPV)-based screening leads to a significant reduction in cervical cancer incidence compared with cytology-based screening only.

Methods: Non-hysterectomised participants ≥30 years underwent co-testing with Papanicolaou (Pap) smear and HR-HPV testing (Hybrid Capture 2; HC2). Women with normal findings had their next screening round after 5 years, and HC2+ and Pap abnormal cases were immediately referred for colposcopy, while cases with discordant findings had repeat testing after 12 months with referral to colposcopy in cases with persistent positive findings.

The yeast C/D box snoRNA U14 adopts a "weak" K-turn like conformation recognized by the Snu13 core protein in solution.

Non-coding RNAs associate with proteins to form ribonucleoproteins (RNPs), such as ribosome, box C/D snoRNPs, H/ACA snoRNPs, ribonuclease P, telomerase and spliceosome to ensure cell viability. The assembly of these RNA-protein complexes relies on the ability of the RNA to adopt the correct bound conformation. K-turn motifs represent ubiquitous binding platform for proteins found in several cellular environment.

Intra- and inter-laboratory agreement of the FAM19A4/mir124-2 methylation test: Results from an international study.

Background: HPV-based cervical screening detects women at an increased risk of cervical cancer and precancer. To differentiate among HPV-positive women those with (pre)cancer, triage testing is necessary. The detection of cancer-associated host-cell DNA methylation (FAM19A4 and hsa-mir124-2) in cervical samples has shown valuable as triage test.

Role of Bicaudal C1 in renal gluconeogenesis and its novel interaction with the CTLH complex.

Altered glucose and lipid metabolism fuel cystic growth in polycystic kidneys, but the cause of these perturbations is unclear. Renal cysts also associate with mutations in Bicaudal C1 (Bicc1) or in its self-polymerizing sterile alpha motif (SAM). Here, we found that Bicc1 maintains normoglycemia and the expression of the gluconeogenic enzymes FBP1 and PEPCK in kidneys.

Crystal Structure of Bicc1 SAM Polymer and Mapping of Interactions between the Ciliopathy-Associated Proteins Bicc1, ANKS3, and ANKS6.

Head-to-tail polymers of sterile alpha motifs (SAM) can scaffold large macromolecular complexes. Several SAM-domain proteins that bind each other are mutated in patients with cystic kidneys or laterality defects, including the Ankyrin (ANK) and SAM domain-containing proteins ANKS6 and ANKS3, and the RNA-binding protein Bicc1. To address how their interactions are regulated, we first determined a high-resolution crystal structure of a Bicc1-SAM polymer, revealing a canonical SAM polymer with a high degree of flexibility in the subunit interface orientations.

Implication of the box C/D snoRNP assembly factor Rsa1p in U3 snoRNP assembly.

The U3 box C/D snoRNA is one key element of 90S pre-ribosome. It contains a 5΄ domain pairing with pre-rRNA and the U3B/C and U3C΄/D motifs for U3 packaging into a unique small nucleolar ribonucleoprotein particle (snoRNP). The RNA-binding protein Snu13/SNU13 nucleates on U3B/C the assembly of box C/D proteins Nop1p/FBL and Nop56p/NOP56, and the U3-specific protein Rrp9p/U3-55K.

Structural Features of the Box C/D snoRNP Pre-assembly Process Are Conserved through Species.

Box C/D small nucleolar ribonucleoparticles (snoRNPs) support 2'-O-methylation of several target RNAs. They share a common set of four core proteins (SNU13, NOP58, NOP56, and FBL) that are assembled on different guide small nucleolar RNAs. Assembly of these entities involves additional protein factors that are absent in the mature active particle.

Functional and Structural Insights of the Zinc-Finger HIT protein family members Involved in Box C/D snoRNP Biogenesis.

Zf–HIT family members share the zf–HIT domain (ZHD), which is characterized by a fold in “treble-clef” through interleaved CCCC and CCHC ZnF motifs that both bind a zinc atom. Six proteins containing ZHD are present in human and three in yeast proteome, all belonging to multimodular RNA/protein complexes involved in gene regulation, chromatin remodeling, and snoRNP assembly. An interesting characteristic of the cellular complexes that ensure these functions is the presence of the RuvBL1/2/Rvb1/2 ATPases closely linked with zf–HIT proteins.

Caregiver preference for reinforcement-based interventions for problem behavior maintained by positive reinforcement.

Social validity of behavioral interventions typically is assessed with indirect methods or by determining preferences of the individuals who receive treatment, and direct observation of caregiver preference rarely is described. In this study, preferences of 5 caregivers were determined via a concurrent-chains procedure. Caregivers were neurotypical, and children had been diagnosed with developmental disabilities and engaged in problem behavior maintained by positive reinforcement.

Bicc1 Polymerization Regulates the Localization and Silencing of Bound mRNA.

Loss of the RNA-binding protein Bicaudal-C (Bicc1) provokes renal and pancreatic cysts as well as ectopic Wnt/β-catenin signaling during visceral left-right patterning. Renal cysts are linked to defective silencing of Bicc1 target mRNAs, including adenylate cyclase 6 (AC6). RNA binding of Bicc1 is mediated by N-terminal KH domains, whereas a C-terminal sterile alpha motif (SAM) self-polymerizes in vitro and localizes Bicc1 in cytoplasmic foci in vivo.

Structure/Function Analysis of Protein-Protein Interactions Developed by the Yeast Pih1 Platform Protein and Its Partners in Box C/D snoRNP Assembly.

In eukaryotes, nucleotide post-transcriptional modifications in RNAs play an essential role in cell proliferation by contributing to pre-ribosomal RNA processing, ribosome assembly and activity. Box C/D small nucleolar ribonucleoparticles catalyze site-specific 2'-O-methylation of riboses, one of the most prevalent RNA modifications. They contain one guide RNA and four core proteins and their in vivo assembly requires numerous factors including (HUMAN/Yeast) BCD1/Bcd1p, NUFIP1/Rsa1p, ZNHIT3/Hit1p, the R2TP complex composed of protein PIH1D1/Pih1p and RPAP3/Tah1p that bridges the R2TP complex to the HSP90/Hsp82 chaperone and two AAA+ ATPases.

Protein Hit1, a novel box C/D snoRNP assembly factor, controls cellular concentration of the scaffolding protein Rsa1 by direct interaction.

Biogenesis of eukaryotic box C/D small nucleolar ribonucleoprotein particles (C/D snoRNPs) involves conserved trans-acting factors, which are proposed to facilitate the assembly of the core proteins Snu13p/15.5K, Nop58p/NOP58, Nop56p/NOP56 and Nop1p/Fibrillarin on box C/D small nucleolar RNAs (C/D snoRNAs). In yeast, protein Rsa1 acts as a platform, interacting with both the RNA-binding core protein Snu13 and protein Pih1 of the Hsp82-R2TP chaperone complex.

High-resolution structural analysis shows how Tah1 tethers Hsp90 to the R2TP complex.

The ubiquitous Hsp90 chaperone participates in snoRNP and RNA polymerase assembly through interaction with the R2TP complex. This complex includes the proteins Tah1, Pih1, Rvb1, and Rvb2. Tah1 bridges Hsp90 to R2TP.

Invertebrate neurophylogeny: suggested terms and definitions for a neuroanatomical glossary.

Background: Invertebrate nervous systems are highly disparate between different taxa. This is reflected in the terminology used to describe them, which is very rich and often confusing. Even very general terms such as 'brain', 'nerve', and 'eye' have been used in various ways in the different animal groups, but no consensus on the exact meaning exists.

Postembryonic development of dorsoventral and longitudinal musculature in Pycnophyes kielensis (Kinorhyncha, Homalorhagida).

We investigated the development of dorsoventral and longitudinal musculature in all postembryonic stages of the kinorhynch Pycnophyes kielensis. Although the earliest stages have only 8 externally separated trunk segments, they already possess dorsoventral muscles for 10 (prospective) trunk segments. The last, 11th, pair is added in the third juvenile stage.