p130‐Angiomotin associates to actin and controls endothelial cell shape

Abstract

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.

Rab13-dependent Trafficking of RhoA Is Required for Directional Migration and Angiogenesis

“…Amot antiserum was raised in rabbit (Dr. Earl Poptic, Hybridoma Core Facility, Lerner Research Institute, Cleveland Clinic Foundation) against the 24 most carboxyl-terminal amino acids, as in Ernkvist et al (21) and used at a 1:1600 dilution. Antiserum to Mupp1 (a gift of Dr. Ronald Javier, Baylor College of Medicine) (22) was used at 1:100 dilution.…”

“…The polyoma middle T-immortalized amot ϩ/ϩ and amot Ϫ/Ϫ ECs and their growth conditions were described previously (21).…”

The Amotl2 Gene Inhibits Wnt/β-Catenin Signaling and Regulates Embryonic Development in Zebrafish

“…These proteins have been demonstrated to play important roles in angiogenesis, cell mobility, cell polarity, and cell-cell junctions by regulating distinct signaling pathways (15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Interestingly, it appears that each Motin family member in human and mice has two isoforms, long and short isoform (14), which function differently in physiological processes (17,(25)(26)(27)(28). However, it is unknown whether Motin members participate in regulation of canonical Wnt signaling pathway.…”

Actin-binding and Cell Proliferation Activities of Angiomotin Family Members Are Regulated by Hippo Pathway-mediated Phosphorylation

“…Amots are characterized by central coiled coil domains and C-terminal PDZ-binding regions (7). Amot-p130 and Amot-p80 are generated by alternative splicing, with the latter lacking the N-terminal 409 amino acids of the former (8).…”

“…Although Amot-p80 promotes the migration of endothelial cells, Amot-p130 does not. The N-terminal extension of Amot-p130 is important for interacting with actin filaments and maintaining cell shape and cell-cell junctions (8,11,12). Recently, Amot family proteins have been identified as interacting proteins of YAP and TAZ and act to antagonize the function of YAP and TAZ (13)(14)(15).…”