Proteolytic activation of angiomotin by DDI2 promotes angiogenesis

The scaffolding protein angiomotin (AMOT) is indispensable for vertebrate embryonic angiogenesis. Here, we report that AMOT undergoes cleavage in the presence of lysophosphatidic acid (LPA), a lipid growth factor also involved in angiogenesis. AMOT cleavage is mediated by aspartic protease DNA damage‐inducible 1 homolog 2 (DDI2), and the process is tightly regulated by a signaling axis including neurofibromin 2 (NF2), tankyrase 1/2 (TNKS1/2), and RING finger protein 146 (RNF146), which induce AMOT membrane localization, poly ADP ribosylation, and ubiquitination, respectively. In both zebrafish and mice, the genetic inactivation of AMOT cleavage regulators leads to defective angiogenesis, and the phenotype is rescued by the overexpression of AMOT‐CT, a C‐terminal AMOT cleavage product. In either physiological or pathological angiogenesis, AMOT‐CT is required for vascular expansion, whereas uncleavable AMOT represses this process. Thus, our work uncovers a signaling pathway that regulates angiogenesis by modulating a cleavage‐dependent activation of AMOT. Synopsis The scaffold protein angiomotin (AMOT) promotes angiogenesis via various mechanisms. This study shows that AMOT is cleaved by protease DDI2 in a highly regulated manner to promote both physiological and pathological angiogenesis in zebrafish and mice. AMOT is cleaved by the aspartic protease DDI2 to produce a C‐terminal AMOT cleavage product in response to lysophosphatidic acid. AMOT cleavage is regulated by concerted activities of the E3 ligase RNF146, tankyrase TNKS1/2, and the membrane‐localized scaffold protein NF2. Uncleavable AMOT inhibits angiogenesis, whereas C‐terminally cleaved AMOT promotes vascular expansion during development and in an oxygen‐induced retinopathy model. Graphical Abstract Cleavage of the scaffold protein AMOT promotes vascular expansion in a manner modulated by membrane localization, poly ADP‐ribosylation, and ubiquitination.