Angiomotin, an 80 kDa protein expressed in endothelial cells, promotes cell migration and invasion, and stabilizes tube formation in vitro. Angiomotin belongs to a new protein family with two additional members, Amotl‐1 and Amotl‐2, which are characterized by conserved coiled‐coil domains and C‐terminal PDZ binding motifs. Here, we report the identification of a 130 kDa splice isoform of angiomotin that is expressed in different cell types including vascular endothelial cells, as well as cytotrophoblasts of the placenta. p130‐Angiomotin consists of a cytoplasmic N‐terminal extension that mediates its association with F‐actin. Transfection of p130‐angiomotin into endothelial cells induces actin fiber formation and changes cell shape. The p130‐angiomotin protein remained associated with actin after destabilization of actin fibers with cytochalasin B. In contrast to p80‐angiomotin, p130‐angiomotin does not promote cell migration and did not respond to angiostatin. We propose that p80‐ and p130‐angiomotin play coordinating roles in tube formation by affecting cell migration and cell shape, respectively.

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