CLPTM1L is a GPI-anchoring pathway component targeted by HCMV.

The GPI-anchoring pathway plays important roles in normal development and immune modulation. MHC Class I Polypeptide-related Sequence A (MICA) is a stress-induced ligand, downregulated by human cytomegalovirus (HCMV) to escape immune recognition. Its most prevalent allele, MICA*008, is GPI-anchored via an uncharacterized pathway. Here, we identify cleft lip and palate transmembrane protein 1-like protein (CLPTM1L) as a GPI-anchoring pathway component and show that during infection, the HCMV protein US9 downregulates MICA*008 via CLPTM1L. We show that the expression of some GPI-anchored proteins (CD109, CD59, and MELTF)-but not others (ULBP2, ULBP3)-is CLPTM1L-dependent, and further show that like MICA*008, MELTF is downregulated by US9 via CLPTM1L during infection. Mechanistically, we suggest that CLPTM1L's function depends on its interaction with a free form of PIG-T, normally a part of the GPI transamidase complex. We suggest that US9 inhibits this interaction and thereby downregulates the expression of CLPTM1L-dependent proteins. Altogether, we report on a new GPI-anchoring pathway component that is targeted by HCMV.

Studying TIGIT activity against tumors through the generation of knockout mice.

The use of antibodies to block inhibitory receptors, primarily anti-PD1 and CTLA4 (known as checkpoint therapy) revolutionized cancer treatment. However, despite these successes, the majority of cancer patients do not respond to the checkpoint treatment, emphasizing the need for development of additional therapies, which are based on other inhibitory receptors. Human TIGIT is an inhibitory receptor expressed by Natural Killer (NK) and T cells and is mainly known to interact with PVR, Nectin-2, Nectin-3, and Nectin-4. Whether mouse TIGIT interacts with all of these ligands is still unclear. Additionally, the in vivo function of TIGIT against tumors is not completely understood. Here, we demonstrate that mouse TIGIT interacts with and is inhibited by mPVR only. Using CRISPR-Cas9 technology, we generated TIGIT-deficient mice and demonstrated that NK cell cytotoxicity and degranulation against two tumor types were lower in WT mice when compared to the TIGIT KO mice. Moreover, in vivo tumor progression was slower in TIGIT KO than in WT mice. Taken together, our data established that mTIGIT has only one ligand, PVR, and that in the absence of TIGIT tumors are killed better both in vitro and in vivo.

Ribosomal Antibiotics: Contemporary Challenges.

Most ribosomal antibiotics obstruct distinct ribosomal functions. In selected cases, in addition to paralyzing vital ribosomal tasks, some ribosomal antibiotics are involved in cellular regulation. Owing to the global rapid increase in the appearance of multi-drug resistance in pathogenic bacterial strains, and to the extremely slow progress in developing new antibiotics worldwide, it seems that, in addition to the traditional attempts at improving current antibiotics and the intensive screening for additional natural compounds, this field should undergo substantial conceptual revision. Here, we highlight several contemporary issues, including challenging the common preference of broad-range antibiotics; the marginal attention to alterations in the microbiome population resulting from antibiotics usage, and the insufficient awareness of ecological and environmental aspects of antibiotics usage. We also highlight recent advances in the identification of species-specific structural motifs that may be exploited for the design and the creation of novel, environmental friendly, degradable, antibiotic types, with a better distinction between pathogens and useful bacterial species in the microbiome. Thus, these studies are leading towards the design of "pathogen-specific antibiotics," in contrast to the current preference of broad range antibiotics, partially because it requires significant efforts in speeding up the discovery of the unique species motifs as well as the clinical pathogen identification.