Journal Article

Identification and Characterization of the Actin-Binding Motif of Phostensin

Lai, Ning-Sheng, Lin, Ta-Hsien, Lu, Ming-Chi, Liu, Su-Qin, Lin, Yu-Shan, Huang, Kuang-Yung, Huang, Hsien-Bin, Chen, Chun-Yu, Huang, Hsien-Lu, Wang, Tzu-Fan

2012

Overview

Phostensin, a protein phosphatase 1 F-actin cytoskeleton-targeting subunit encoded by KIAA1949, consists of 165 amino acids and caps the pointed ends of actin filaments. Sequence alignment analyses suggest that the C-terminal region of phostensin, spanning residues 129 to 155, contains a consensus actin-binding motif. Here, we have verified the existence of an actin-binding motif in the C-terminal domain of phostensin using colocalization, F-actin co-sedimentation and single filament binding assays. Our data indicate that the N-terminal region of phostensin (1–129) cannot bind to actin filaments and cannot retard the pointed end elongation of gelsolin-actin seeds. Furthermore, the C-terminal region of phostensin (125–165) multiply bind to the sides of actin filaments and lacks the ability to block the pointed end elongation, suggesting that the actin-binding motif is located in the C-terminal region of the phostensin. Further analyses indicate that phostensin binding to the pointed end of actin filament requires N-terminal residues 35 to 51. These results suggest that phostensin might fold into a rigid structure, allowing the N-terminus to sterically hinder the binding of C-terminus to the sides of actin filament, thus rendering phostensin binding to the pointed ends of actin filaments.

• Publisher: MDPI AG,Molecular Diversity Preservation International (MDPI)
• Subject: Actin Cytoskeleton - genetics / Actin Cytoskeleton - metabolism / Actins - genetics / Actins - metabolism / Amino Acid Motifs / Amino acids / Animals / Binding Sites / Cytoskeleton / Dogs / Electronic mail systems / Leukocytes / Madin Darby Canine Kidney Cells / Molecular biology / Phosphatase / Protein Phosphatase 1 - genetics / Protein Phosphatase 1 - metabolism / Proteins / Sedimentation & deposition