Ccdc38 is required for sperm flagellum biogenesis and male fertility in mouse

Sperm flagellum is essential for male fertility, defects in flagellum biogenesis are associated with male infertility. Deficiency of CCDC42 is associated with malformation of the mouse sperm flagella. Here, we find that the testis-specific expressed protein CCDC38 (coiled coil domain containing 38) interacts with CCDC42 and localizes on manchette and sperm tail during spermiogenesis. Inactivation of CCDC38 in male mice results in distorted manchette, multiple morphological abnormalities of the flagella (MMAF) of spermatozoa, and eventually male sterility. Furthermore, we find that CCDC38 interacts with intra-flagellar transport protein 88 (IFT88) as well as the outer dense fibrous 2 (ODF2), and its depletion reduces the transportation of ODF2 to flagellum. Altogether, our results uncover the essential role of CCDC38 during sperm flagellum biogenesis, and suggesting the defects of these genes might be associated with male infertility in human being.

Structural basis of NLR activation and innate immune signalling in plants

Animals and plants have NLRs (nucleotide-binding leucine-rich repeat receptors) that recognize the presence of pathogens and initiate innate immune responses. In plants, there are three types of NLRs distinguished by their N-terminal domain: the CC (coiled-coil) domain NLRs, the TIR (Toll/interleukin-1 receptor) domain NLRs and the RPW8 (resistance to powdery mildew 8)-like coiled-coil domain NLRs. CC-NLRs (CNLs) and TIR-NLRs (TNLs) generally act as sensors of effectors secreted by pathogens, while RPW8-NLRs (RNLs) signal downstream of many sensor NLRs and are called helper NLRs. Recent studies have revealed three dimensional structures of a CNL (ZAR1) including its inactive, intermediate and active oligomeric state, as well as TNLs (RPP1 and ROQ1) in their active oligomeric states. Furthermore, accumulating evidence suggests that members of the family of lipase-like EDS1 (enhanced disease susceptibility 1) proteins, which are uniquely found in seed plants, play a key role in providing a link between sensor NLRs and helper NLRs during innate immune responses. Here, we summarize the implications of the plant NLR structures that provide insights into distinct mechanisms of action by the different sensor NLRs and discuss plant NLR-mediated innate immune signalling pathways involving the EDS1 family proteins and RNLs.

TRIM29 in Cutaneous Squamous Cell Carcinoma

Tripartite motif (TRIM) proteins play important roles in a wide range of cell physiological processes, such as signal transduction, transcriptional regulation, innate immunity, and programmed cell death. TRIM29 protein, encoded by the ATDC gene, belongs to the RING-less group of TRIM protein family members. It consists of four zinc finger motifs in a B-box domain and a coiled-coil domain, and makes use of the B-box domain as E3 ubiquitin ligase in place of the RING. TRIM29 was found to be involved in the formation of homodimers and heterodimers in relation to DNA binding; additional studies have also demonstrated its role in carcinogenesis, DNA damage signaling, and the suppression of radiosensitivity. Recently, we reported that TRIM29 interacts with keratins and FAM83H to regulate keratin distribution. Further, in cutaneous SCC, the expression of TRIM29 is silenced by DNA methylation, leading to the loss of TRIM29 and promotion of keratinocyte migration. This paper reviews the role of TRIM family proteins in malignant tumors, especially the role of TRIM29 in cutaneous SCC.

KIF3B gene silent variant leading to sperm morphology and motility defects and male infertility

Sperm structural and functional defects are leading causes of male infertility. Patients with immotile sperm disorders suffer from axoneme failure and show a significant reduction in sperm count. The kinesin family member 3B (KIF3B) is one of the genes involved in the proper formation of sperm with a critical role in intraflagellar and intramanchette transport. A part of exon 2 and exons 3–5 of the KIF3B encodes a protein coiled-coil domain that interacts with IFT20 from the IFT protein complex. In the present study, the coding region of KIF3B coiled-coil domain was assessed in 88 oligoasthenoteratozoospermic patients, and the protein expression was evaluated in the mature spermatozoa of the case and control groups using immunocytochemistry and western blotting. According to the results, there was no genetic variation in the exons 3–5 of the KIF3B, but a new A > T variant was identified within the exon 2 in 30 patients, where nothing was detected in the control group. In contrast to healthy individuals, significantly reduced protein expression was observable in oligoasthenoteratozoospermic (OAT) patients carrying variation where protein organization was disarranged, especially in the principal piece and midpiece of the sperm tail. Besides, the protein expression level was lower in the patients’ samples compared to that of the control group. According to the results of the present study the NM_004798.3:c.1032A > T, p.Pro344 = variant; which has been recently submitted to the Clinvar database; although synonymous, causes alterations in the transcription factor binding site, exon skipping, and also exonic splicing enhancer-binding site. Therefore, KIF3B can play an important role in spermatogenesis and the related protein reduction can cause male infertility.

IRAG2 Interacts with IP3-Receptor Types 1, 2, and 3 and Regulates Intracellular Ca2+ in Murine Pancreatic Acinar Cells

The inositol 1,4,5-triphosphate receptor-associated 2 (IRAG2) is also known as Jaw1 or lymphoid-restricted membrane protein (LRMP) and shares homology with the inositol 1,4,5-triphosphate receptor-associated cGMP kinase substrate 1 (IRAG1). IRAG1 interacts with inositol trisphosphate receptors (IP3 receptors /IP3R) via its coiled-coil domain and modulates Ca2+ release from intracellular stores. Due to the homology of IRAG1 and IRAG2, especially in its coiled-coil domain, it is possible that IRAG2 has similar interaction partners like IRAG1 and that IRAG2 also modulates intracellular Ca2+ signaling. In our study, we localized IRAG2 in pancreatic acinar cells of the exocrine pancreas, and we investigated the interaction of IRAG2 with IP3 receptors and its impact on intracellular Ca2+ signaling and exocrine pancreatic function, like amylase secretion. We detected the interaction of IRAG2 with different subtypes of IP3R and altered Ca2+ release in pancreatic acinar cells from mice lacking IRAG2. IRAG2 deficiency decreased basal levels of intracellular Ca2+, suggesting that IRAG2 leads to activation of IP3R under unstimulated basal conditions. Moreover, we observed that loss of IRAG2 impacts the secretion of amylase. Our data, therefore, suggest that IRAG2 modulates intracellular Ca2+ signaling, which regulates exocrine pancreatic function.

Protein Targeting to Starch Synthase 1, a Functional Protein of Starch Biosynthesis in Wheat (Triticum Aestivum L.)

In cereal endosperm, native starch comprising amylose and amylopectin is synthesized by the coordinated activities of several pathway enzymes. Amylose in starch influences its physio-chemical properties resulting in several human health benefits. The Granule-Bound Starch Synthase I (GBSSI) is the most abundant starch-associated protein. GBSSI lacks dedicated Carbohydrate-binding module (CBM). Previously, Protein Targeting Starch Synthase 1 (PTST1) was identified as a crucial protein for the localization of GBSSI to the starch granules in Arabidopsis. The function of its homologous protein in the wheat endosperm is not known. In this study, TaPTST1, an AtPTST1 homolog, containing a CBM and a coiled-coil domain was identified in wheat. Protein-coding nucleotide sequence of TaPTST1 from Indian wheat variety ‘C 306’ was cloned and characterized. Homology modelling and molecular docking suggested the potential interaction of TaPTST1 with glucans and GBSSI. The TaPTST1 expression was higher in wheat grain than the other tissues, suggesting a grain-specific function. In vitro binding assays demonstrated different binding affinities of TaPTST1 for native starch, amylose, and amylopectin. Furthermore, the immunoaffinity pull-down assay revealed that TaPTST1 directly interacts with GBSSI, and the interaction is mediated by a coiled-coil domain. The direct protein-protein interaction was further confirmed by bimolecular fluorescence complementation assay (BiFC) in planta. Based on our findings we postulate a functional role for TaPTST1 in starch metabolism by targeting GBSSI to starch granules in wheat endosperm.

Unconventional conservation reveals structure-function relationships in the synaptonemal complex

Functional requirements constrain protein evolution, commonly manifesting in a conserved amino acid sequence. Here, we extend this idea to secondary structural features by tracking their conservation in essential meiotic proteins with highly diverged sequences. The synaptonemal complex (SC) is a ~100-nm-wide ladder-like meiotic structure present in all eukaryotic clades, where it aligns parental chromosomes and regulates exchanges between them. Despite the conserved ultrastructure and functions of the SC, SC proteins are highly divergent within Caenorhabditis. However, SC proteins have highly conserved length and coiled-coil domain structure. We found the same unconventional conservation signature in Drosophila and mammals, and used it to identify a novel SC protein in Pristionchus pacificus, Ppa-SYP-1. Our work suggests that coiled-coils play wide-ranging roles in the structure and function of the SC, and more broadly, that expanding sequence analysis beyond measures of per-site similarity can enhance our understanding of protein evolution and function.

Downregulation of the Coiled-Coil Domain Containing 80 and Its Perspective Mechanisms in Ovarian Carcinoma: A Comprehensive Study

Introduction. We aimed to explore the downregulation of the coiled-coil domain containing 80 (CCDC80) and its underlying molecular mechanisms in ovarian carcinoma (OVCA). Materials/Methods. Immunohistochemical staining was performed to confirm the expression status of CCDC80 protein. Combining the data from in-house tissue microarrays and high-throughput datasets, we identified the expression level of CCDC80 in OVCA. We utilized cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT) algorithm and single-sample gene set enrichment analysis (ssGSEA) to explore the relationship between CCDC80 and the tumor microenvironment (TME) landscape in OVCA. Pathway enrichment, function annotation, and transcription factor (TFs) exploration were conducted to study the latent molecular mechanisms. Moreover, the cell line data in the Genomics of Drug Sensitivity in Cancer (GDSC) database was used to discover the relationship between CCDC80 and drug sensitivity. Results. An integrated standard mean difference (SMD) of −0.919 (95% CI: −1.515–0.324, P = 0.002 ) identified the downregulation of CCDC80 in OVCA based on 1048 samples, and the sROC ( AUC = 0.76 ) showed a moderate discriminatory ability of CCDC80 in OVCA. The fraction of infiltrating naive B cells showed significant differences between the high- and low-CCDC80 expression groups. Also, CCDC80-related genes are enriched in the Ras signaling pathway and metabolic of lipid. Nuclear receptor subfamily three group C member 1 (NR3C1) may be an upstream TF of CCDC80, and CCDC80 may be related to the sensitivity of mitocycin C and nilotinib. Conclusion. CCDC80 was downregulated in OVCA and may play a role as a tumor suppressor in OVCA.