SPATA 2 promotes CYLD activity and regulates TNF ‐induced NF ‐κB signaling and cell death

Abstract

K63- and Met1-linked ubiquitylation are crucial posttranslational modifications for TNF receptor signaling. These non-degradative ubiquitylations are counteracted by deubiquitinases (DUBs), such as the enzyme CYLD, resulting in an appropriate signal strength, but the regulation of this process remains incompletely understood. Here, we describe an interaction partner of CYLD, SPATA2, which we identified by a mass spectrometry screen. We find that SPATA2 interacts via its PUB domain with CYLD, while a PUB interaction motif (PIM) of SPATA2 interacts with the PUB domain of the LUBAC component HOIP SPATA2 is required for the recruitment of CYLD to the TNF receptor signaling complex upon TNFR stimulation. Moreover, SPATA2 acts as an allosteric activator for the K63- and M1-deubiquitinase activity of CYLD In consequence, SPATA2 substantially attenuates TNF-induced NF-κB and MAPK signaling. Conversely, SPATA2 is required for TNF-induced complex II formation, caspase activation, and apoptosis. Thus, this study identifies SPATA2 as an important factor in the TNF signaling pathway with a substantial role for the effects mediated by the cytokine.

SPATA2 regulates the activation of RIPK1 by modulating linear ubiquitination

“…S7A; Elliott et al 2016;Schlicher et al 2016;Wagner et al 2016). We found that CYLD was not recruited to the TNF-RSC in Spata2 −/− MEFs like it was in wild-type MEFs upon TNFα stimulation but was restored by the expression of a Spata2 expression vector (Spata2 + cells) ( Fig.…”

“…CYLD is recruited to the TNF-RSC by its interaction with the LUBAC in association with spermatogenesis-associated 2 (SPATA2) (Kupka et al 2016;Schlicher et al 2016;Wagner et al 2016). Spata2 was identified as a gene involved in mediating necroptosis from a genome-wide siRNA screen .…”

“…On the other hand, a conserved PUB-interacting motif in SPATA2 binds with the HOIP PUB domain. Spata2-deficient cells show resistance to RIPK1-dependent apoptosis (RDA) and necroptosis Kupka et al 2016;Schlicher et al 2016;Wagner et al 2016). However, it is still not clear how SPATA2 might regulate the activation of the RIPK1 kinase.…”

Mechanisms of regulation and diversification of deubiquitylating enzyme function

“…Similarly, interaction of USP10 with the Ras-GTPase-activating protein G3BP1 affects the catalytic activity of USP10, and the G3BP1-USP10 complex regulates the formation of stress granules in response to phosphorylation of eukaryotic initiation factor 2α or inhibition of eukaryotic initiation factor 4A (Kedersha et al, 2016;Soncini et al, 2001). Furthermore, spermatogenesis-associated protein 2 (SPATA2) acts as a scaffold protein that links CYLD to HOIL-1L-interacting protein (HOIP; also known as RNF31), an E3 ligase component of the linear ubiquitin chain assembly complex (LUBAC), and so controls the outcome of tumour necrosis factor receptor 1 (TNFR1; also known as TNFRSF1A)-mediated signalling (Elliott et al, 2016;Kupka et al, 2016;Schlicher et al, 2016;Wagner et al, 2016). In a similar manner, interactions of USP8 and AMSH (also known as STAMBP) with signal transducing adapter molecule 1 (STAM) and endosomal sorting complex required for transport III (ESCRT-III) components ensure the endosomal localization of these DUBs and thereby support their function in endocytosis (Clague and Urbe, 2017;Millard and Wood, 2006).…”

Molecular basis for specificity of the Met1-linked polyubiquitin signal

“…Recently, four independent studies have identified a previously uncharacterised protein, spermatogenesis-associated factor 2 (SPATA2), as a critical component that links CYLD to HOIP [119–122]. SPATA2 and SPATA2L had been previously identified in a DUB-wide proteomics screen as a strong interactor with CYLD [113].…”