Expression profile of the STAND protein Nwd1 in the developing and mature mouse central nervous system

Abstract

The orchestrated events required during brain development, as well as the maintenance of adult neuronal plasticity, highly depend on the accurate responses of neuronal cells to various cellular stress or environmental stimuli. Recent studies have defined a previously unrecognized, broad class of multidomain proteins, designated as signal transduction ATPases with numerous domains (STAND), which comprises a large number of proteins, including the apoptotic peptidase activating factor 1 (Apaf1) and nucleotide-binding oligomerization domain-like receptors (NLRs), central players in cell death and innate immune responses, respectively. Although the involvement of STANDs in the central nervous system (CNS) has been postulated in terms of neuronal development and function, it remains largely unclear. Here, we identified Nwd1 (NACHT and WD repeat domain-containing protein 1), as a novel STAND protein, expressed in neural stem/progenitor cells (NSPCs). Structurally, Nwd1 was most analogous to the apoptosis regulator Apaf1, also involved in mitosis and axonal outgrowth regulation in the CNS. Using a specific antibody, we show that, during the embryonic and postnatal period, Nwd1 is expressed in nestin-positive NSPCs in vivo and in vitro, while postnatally it is found in terminally differentiated neurons and blood vessels. At the subcellular level, we demonstrate that Nwd1 is preferentially located in the cytosolic compartment of cultured NSPCs, partially overlapping with cytochrome c. These observations imply that Nwd1 might be involved in the neuronal lineage as a new STAND gene, including having a pro-apoptotic or nonapoptotic role, similar to Apaf1.

Nwd1 regulates neuronal differentiation and migration through purinosome formation in the developing cerebral cortex

“…We previously reported the substantial expression levels of Nwd1 in VZ/SVZ and immature neurons (Yamada and Sakakibara, 2018). Accordingly, a larger number of cells overexpressing Nwd1 remained within VZ/SVZ (Figure 1).…”

“…Based on its structural similarity to other STAND-family proteins (Leipe et al, 2004), we hypothesized that the N-terminal region of Nwd1 serves as an effector domain by which the protein binds signaling molecule(s) to trigger self-oligomerization mediated by the NACHT domain and WD40 repeats. The N-terminal region of Nwd1 contains a DUF4062 motif, a functionally uncharacterized motif found in bacteria and eukaryotes (Yamada and Sakakibara, 2018). The screening of a mouse brain library using a bait encoding the N-terminal region of Nwd1 led to the isolation of 14 putative…”

“…Previously, we identified the NACHT and WD repeat domain-containing protein 1 (Nwd1) gene and showed that the Nwd1 protein is expressed in NSPCs and immature neurons in the embryonic mice cerebral cortex (Yamada and Sakakibara, 2018). The Nwd1 protein contains a NACHT domain, which is predicted to have nucleoside-triphosphatase (NTPase) activity, in the central region and a cluster of WD40 repeats at the C terminus.…”

“…The Nwd1 protein contains a NACHT domain, which is predicted to have nucleoside-triphosphatase (NTPase) activity, in the central region and a cluster of WD40 repeats at the C terminus. Based on the domain structure, Nwd1 is designated as a novel member of signal transduction ATPases with numerous domains (STAND) protein superfamily and is conserved across species, including zebrafish, mice, rats, monkeys, and humans (Yamada and Sakakibara, 2018). Other members of the STAND protein family often mediate ligand-induced self-oligomerization to form the giant multiprotein complex critical for various important cellular responses; e.g., the apoptotic peptidase activating factor 1 (Apaf1) and nucleotide-binding oligomerization domain-like receptors (NLRs) induce the assembly of large multiprotein complexes, the "apoptosome" and "inflammasome", and play central roles in cell death and innate immune responses, respectively (Cai et al, 2017;Dorstyn et al, 2018;Leipe et al, 2004).…”

“…Other members of the STAND protein family often mediate ligand-induced self-oligomerization to form the giant multiprotein complex critical for various important cellular responses; e.g., the apoptotic peptidase activating factor 1 (Apaf1) and nucleotide-binding oligomerization domain-like receptors (NLRs) induce the assembly of large multiprotein complexes, the "apoptosome" and "inflammasome", and play central roles in cell death and innate immune responses, respectively (Cai et al, 2017;Dorstyn et al, 2018;Leipe et al, 2004). Although the cellular function of Nwd1 remains unclear, its domain structure is analogous to Apaf1, an essential molecule for apoptosome assembly, which is required for apoptosis initiation (Dorstyn et al, 2018;Yamada and Sakakibara, 2018). This study shows that Nwd1 regulates NSPC proliferation and neuronal migration through the control of purinosome formation during cortical development.…”