TERF2IP S205 Phosphorylation Instigates Pathological Flow-induced Plaque Erosion By Reducing LATS1/2 Expression

Pathologic wall shear stress (WSS) of both high and low WSS can contribute to plaque destabilization and subsequent plaque erosion and rupture. The contribution of both ECs proliferation and apoptosis in plaque erosion has been proposed, but how both EC proliferation and apoptosis can be induced simultaneously by pathological flow (high (h-) and disturbed (d-) flow) has yet to be well-studied. The depletion of LATS1/2 significantly enhanced lesions at the d- and h-flow areas. We found that both d- and h-flow (36 dyn/cm 2 ) can decrease LATS1/2 expression but not intermediate normal laminar flow (l-flow: 12 dyn/cm 2 ). Pathological flow and depletion of LATS1/2 increased EC proliferation, apoptosis, and tissue factor expression, but normal l-flow did not. TERF2IP is a member of the shelterin complex of the telomere. Previously, we reported that TERF2IP S205 phosphorylation had a crucial role in d-flow-induced EC senescence and apoptosis induction. Transduction of adenovirus containing TERF2IP S205A mutation significantly inhibited the d-flow-induced reduction of LATS1/2 expression. No change in LATS1/2 mRNA levels after d-flow was detected and the protease inhibitor of MG132 inhibited the d-flow-induced reduction of LATS1/2 expression, suggesting the involvement of protein degradation in the reduction of LATS1/2. The role of MKRN1 (ubiquitin E3 ligase) in senescence has been reported, and we found that the depletion of MKRN1 significantly inhibited the d-flow-induced LATS1/2 reduction, suggesting that LATS1/2 is a novel MKRN1 substrate. Importantly, d-flow increased TERF2IP and MKRN1 association; this association was inhibited by TERF2IP S205A mutation. Overexpression of the TERF2IP c-myb domain inhibited the TERF2IP-MKRN1 association, suggesting that this TERF2IP site is a binding site of TERF2IP with MKRN1. We observed continuous binding of TERF2IP and LATS1/2 until the reduction of LATS1/2 expression by d-flow, suggesting that TERF2IP S205 phosphorylation recruits a trinary complex of TERF2IP-MKRN1-LATS1/2, which promotes LATS1/2 degradation. These data suggest the role of TERF2IP S205 phosphorylation in down-regulating LATS1/2 expression, resulting in EC senescence and subsequent plaque erosion mediated by the pathological flow.