Wiskott-Aldrich syndrome (WAS), an X-linked recessive condition characterized by lymphocyte deficiency, thrombocytopenia and eczema is an example of one disorder which could benefit from having WASP family genes mutated and present as mutant variants; further members such as N-WASP were discovered through proteomics searches.
WASPs bind directly to membrane phosphoinositides through their proline-rich domains, helping orient membrane curvature and promote actin polymerization for unique membrane-cytoskeleton architectures.
Detection of WAVEs
Recent studies have demonstrated the power of electromagnetic waves to devastate pathogenic viruses’ RNA. Wu [1] exposed MS2 virus RNA directly to 2450 MHz electromagnetic waves, and his results demonstrated that its expression decreased with increasing power density – this finding is consistent with previous research showing UHF electromagnetic waves can damage DNA; humans encode WASP- and WAVE-family proteins with nine or twelve exons; this family of proteins are prevalently expressed in brain tissue while moderate expression levels exist among hematopoietic cells.
These proteins possess several conserved domains, including the VCA region which contains two motifs that interact with Arp2/3 complex and are necessary for actin filament formation. Furthermore, other domains, including WH1 domain and SCAR domain are highly conserved between species; an TBLAST search of Ensembl zebrafish genome Zv8 revealed four human WASP and two of which were WAVE1; in contrast budding yeast only has one WASP homolog (two being WAVE1). Therefore phylogenetic analysis of WASP and WAVE homologs is an invaluable way of uncovering evolutionary relationships among proteins; we constructed trees using alignments between V and C regions using neighbor-joining method to reconstruct trees using neighbor joining.
Detection of WASPs
Wiskott-Aldrich Syndrome Protein (WASP) and WAVE-Family Verprolin Homologue Protein (WAVE) family proteins are fundamental actin cytoskeleton reorganizers found in all eukaryotic organisms. Their core function is to receive signals from Rho-family small GTPases, activate the Arp2/3 complex and rapidly form actin filaments within cells. WASPs and WAVEs work in collaboration with other molecules to shape various actin architectures, including endocytic vesicles, filopodia and podosomes/invadopodia – important structures that facilitate cell motility, movement and secretion. WASPs and WAVEs are controlled by several factors which ensure their appropriate activation or degradation; mutations of some genes encoding WASPs/WAVEs cause human diseases such as neurodegeneration or cancer.
Phylogenetic analyses demonstrate that both WASP and N-WASP were present in the common ancestor of jawed fish and mammals. Their amino-terminal end, specifically their WH1/EVH1 domains, contain amphipathic clefts that interact with hydrophobic faces of GBD/CRIB domain’s amino-terminal end to form an autoinhibitory interaction; when bound, VCA region autoinhibition occurs causing autoinhibition; Phosphatidylinositol-(4,5)-bisphosphate activates Arp2/3 complex leading to actin filament formation and filament production.
WASPs play an essential role in cell motility, but also have numerous other cellular processes including division, signaling and adhesion. Unfortunately, their regulatory mechanisms remain unknown; additionally they serve as targets for anticancer drugs as aberrant upregulation can promote cancer metastasis and resistance to chemotherapy treatments.
We used RNAi to ventralize or dorsalize embryos of Nasonia vitripennis jewel wasp, and RNAseq to quantify transcriptome-wide expression levels. We identified over 100 genes that are uniquely dorsal or ventral embryo regulated, such as transcription factors and cytoskeletal proteins. Most of these genes play an essential role in shaping embryos’ dorsoventral axis, suggesting they play a significant part in driving the various cell and tissue behaviors seen during gastrulation. Genomic approaches are being employed to identify upstream regulatory mechanisms that may account for these differences in embryo development between dorsal and ventral embryos. Our goal is to establish whether regulators controlling WAVEs and other cellular motors share similar control mechanisms across both embryo types.
Detection of WAVE-like proteins
WAVE proteins are cytoskeletal regulatory factors that are known to regulate actin assembly within cells. WAVEs play an integral part in cell migration by encouraging microtubule aggregation into macropinosome-like structures and aiding actin filament formation – this allows cells to migrate into new territory or towards stimuli sites more quickly. In addition, WAVEs promote organelle and vesicle movement as well as filopodia and podosome formation by binding to microtubules as well as molecules which promote formation – thus aiding cell migration into new territories or towards sites of stimuli. To accomplish these feats of course WAVEs must first bind microtubules before moving onward to other molecules involved in their formation – WAVEs must then interact with multiple other molecules involved before finally becoming active again to generate these structures that assist migration.
The WAVE protein family in mammals comprises five genes: WASP, N-WASP, WAVE1, WAVE2/SCAR1 and WAVE3. Each gene encodes for 498 to 559 amino acids. Proteins encoded from these exons share an amino-terminal domain known as VCA region that includes N-WASP homology 1 (WH1) and Verprolin homology Homology (EVH) domains which bind with Arp2/3 complex; additionally they feature acidic regions which bind with an acidic domain called P115/SHIP Guanosine triphosphate Binding Domain which may help protect these proteins against proteasomal degradation.
Recent research has demonstrated how WASPs and WAVEs cooperate to form specific membrane-cytoskeleton architectures. N-WASP is necessary for the formation of endocytic vesicles and filopodia, while WAVEs play an essential role in podosome formation and invadopodia formation. Yet how these proteins assemble their specific architectures remains unknown; one hypothesis suggests they act as molecular bridges connecting membranes to Arp2/3 complex.
WASP and WAVE family proteins have long been recognized for their membrane deforming abilities, with WASPs specifically being linked with their ability to form actin-based membrane curvatures. FBP17’s EFC/F-BAR domain allows it to trigger N-WASP activation via coordination of membrane invagination and actin polymerization; however, its exact relationship to curvatures underlying membrane remains to be established.
An outstanding question in gene expression studies relates to how the gradients driving gene expression waves are generated and altered. One theory suggests that periodic or nonperiodic waves arise depending on the strength of a cellular signal that modulates either molecular clock speed or genetic cascade speeds.
Detection of WAVE-like regions
Discovering WAVE-like regions in human DNA is an integral component of understanding how gene expression waves form, as it provides key insights into their production. Furthermore, it identifies genes driving these waves that could provide opportunities for drug development.
According to the Enhancer Switching model, each gene can create an expression wave by interacting with another gene and producing dynamic enhancers that produce the initial wave; once created, static enhancers then arrest this movement into a stable gene expression domain that then travels throughout other cells as an expression wave.
Recent discoveries by multiple groups independently have identified a protein with similarity to WASP (Scarlet-like protein with ARNT-binding motif) and SCAR1 (Scarlet-like protein with N-WASP-binding motif), and may play an essential role in cell-mediated immune responses by modulating the expression of cytokines and chemokines.
These proteins not only share similar amino acid sequences but also possess structural similarities. Both contain the conserved WH1/EVH1 domain responsible for binding to basic helix-loop-helix transcription factors as well as the C-terminal domain that regulates phosphorylation of specific amino acids in DNA.
Both wave-1 and wave-2 samples displayed a high incidence of amino acid substitutions, deletions, and transversions; however, wave-2 samples displayed higher frequency C to T transitions likely due to their pooled sample pool containing the GH clade and its subsequent mutation into G to T transitions resulting in G to T transitions primarily originating in Bangladesh during Wave 2. Furthermore, due to G to T transitions occurring within its virus genome this might explain why its prevalence predominated during Bangladesh Wave 2 samples.
Genetic analysis revealed that SARS-CoV-2 variants with certain spike protein mutations are more transmissible than others, including changes to its receptor-binding domain (RBD). Docking analysis between ACE2 receptor and RBD of spike protein demonstrated that highly selected variants bind ACE2 receptor with high affinity. Despite these mutations, SARS-CoV-2 remains susceptible to inhibition by various inhibitors.