Identification and characterization of the actin-binding motif of Phostensin

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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


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.

Original languageEnglish
Pages (from-to)15967-15982
Number of pages16
JournalInternational Journal Of Molecular Sciences
Issue number12
StatePublished - Dec 2012


  • Actin filament
  • KIAA1949
  • Phostensin
  • Protein phosphatase 1


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