NDR Kinase Is Activated by RASSF1A/MST1 in Response to Fas Receptor Stimulation and Promotes Apoptosis

Abstract

Human NDR1 and 2 (NDR1/2) are serine-threonine protein kinases in a subgroup of the AGC kinase family. The mechanisms of physiological NDR1/2 activation and their function remain largely unknown. Here we report that Fas and TNF-alpha receptor stimulation activates human NDR1/2 by promoting phosphorylation at the hydrophobic motif (Thr444/442). Moreover, NDR1/2 are essential for Fas receptor-induced apoptosis as shown by the fact that NDR knockdown significantly reduced cell death whereas overexpression of the NDR1 kinase further potentiated apoptosis. Activation of NDR1/2 by death receptor stimulation is mediated by the tumor suppressor RASSF1A. Furthermore, RASSF1A-induced apoptosis largely depends on the presence of NDR1/2. Fas receptor stimulation promoted direct phosphorylation and activation of NDR1/2 by the mammalian STE20-like kinase 1 (MST1), a downstream effector of RASSF1A. Concurrently, the NDR1/2 coactivator MOB1 induced MST1-NDR-MOB1 complex formation, which is crucial for MST1-induced NDR1/2 phosphorylation upon induction of apoptosis. Our findings identify NDR1/2 as novel proapoptotic kinases and key members of the RASSF1A/MST1 signaling cascade.

PKB/AKT phosphorylation of the transcription factor Twist-1 at Ser42 inhibits p53 activity in response to DNA damage

“…Targeting sequence used for generating shRNA against human Twist-1 was as follows: 5 0 -GCTGAGCAA GATTCAGACC-3 0 . Targeting sequences used for generating shRNA against human PKB and firefly luciferase were as described previously (Bozulic et al, 2008;Vichalkovski et al, 2008). The reporter plasmids p21 Waf1 -Luc (el-Deiry et al, 1993) and Bax-Luc (Fogal et al, 2000) were as published, E-cadherin-Luc construct was a kind gift of A. DiFeo (The Mount Sinai School of Medicine).…”

Hippo signalling in the G2/M cell cycle phase: Lessons learned from the yeast MEN and SIN pathways

“…In contrast, the regulation of MST1/2 by RASSF1A has been studied more extensively. In human cells, RASSF1A signals through MST/LATS1 to induce apoptosis [105][106][107], and can also trigger apoptosis by MST1/NDR signalling [108]. Part of the mode of action appears to be that RASSF1A protects MST1/2 from dephosphorylation by PP2A to induce apoptosis [109].…”

“…Part of the mode of action appears to be that RASSF1A protects MST1/2 from dephosphorylation by PP2A to induce apoptosis [109]. Whatever the case, RASSF1A has been repeatedly reported as an activator of MST1/2 signalling [105][106][107][108]110]. RASSF1A can form complexes with MST1/2 and WW45 through conserved SARAH domains [71,82,83,111], which seems to play a role in Hippo dependent and independent apoptotic signalling [112].…”

Mer receptor tyrosine kinase promotes invasion and survival in glioblastoma multiforme

“…29 Assessing the apoptotic fraction of cells by measuring Dcm after etoposide treatment, we recorded increases in this fraction from 4.5% to 59.3% and from 5.1% to 56.9% in empty vector-and MerTK-mut-expressing U373 …”