The ability of AIF-1 to activate human vascular smooth muscle cells is lost by mutations in the EF-hand calcium-binding region |
| |
Authors: | Autieri Michael V Chen Xing |
| |
Affiliation: | Department of Physiology, Cardiovascular Research Center, Temple University School of Medicine, Room 810, MRB 3420 N. Broad Street, Philadelphia PA 19140, USA. mautieri@temple.edu |
| |
Abstract: | Allograft Inflammatory Factor-1 (AIF-1) is a cytoplasmic calcium-binding protein expressed in vascular smooth muscle cells (VSMC) in response to injury or cytokine stimulation. AIF-1 contains a partially conserved EF-hand calcium-binding domain, and participates in VSMC activation by activation of Rac1 and induction of Granulocyte-Colony Stimulating Factor (G-CSF) expression; however, the mechanism whereby AIF-1 mediates these effects is presently uncharacterized. To determine if calcium binding plays a functional role in AIF-1 activity, a single site-specific mutation was made in the EF-hand calcium-binding domain to abrogate binding of calcium (AIF-1DeltaA), which was confirmed by calcium overlay. Functionally, similar to wild-type AIF-1, AIF-1DeltaA was able to polymerize F-actin in vitro. However, in contrast to wild-type AIF-1, over-expression of AIF-1DeltaA was unable to increase migration or proliferation of primary human VSMC. Further, it was unable to activate Rac1, or induce G-CSF expression to the degree as wild-type AIF-1. Taken together, modification of the wild-type EF-hand domain and native calcium-binding activity results in a loss of AIF-1 function. We conclude that appropriate calcium-binding potential is critical in AIF-1-mediated effects on VSMC pathophysiology, and that AIF-1 activity is mediated by Rac1 activation and G-CSF expression. |
| |
Keywords: | Allograft Inflammatory Factor-1 Calcium-binding domain Vascular smooth muscle cell |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|