Identification of the high molecular weight isoform of phostensin

  • Int J Mol Sci. 2014 Jan 15;15(1):1068-79. doi: 10.3390/ijms15011068.
Yu-Shan Lin  1 ,  Hsien-Lu Huang  2 ,  Wei-Ting Liu  3 ,  Ta-Hsien Lin  4 ,  Hsien-Bin Huang  5
Affiliations
  • 1. Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan. [email protected].
  • 2. Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan. [email protected].
  • 3. Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan. [email protected].
  • 4. Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan. [email protected].
  • 5. Department of Life Science and Institute of Molecular Biology, National Chung Cheng University, Chia-Yi 62102, Taiwan. [email protected].
PMID: 24434620 DOI: 10.3390/ijms15011068
Abstract

Phostensin is encoded by KIAA1949. 5'-RACEanalysis has been used to identify the translation start site of phostensin mRNA, indicating that it encodes 165 Amino acids with an apparent molecular weight of 26 kDa on SDS-PAGE. This low-molecular-weight phostensin is present in human peripheral blood mononuclear cells and many leukemic cell lines. Phostensin is a protein phosphatase-1(PP1) binding protein. It also contains one actin-binding motif at its C-terminal region and binds to the pointed ends of actin filaments, modulating actin dynamics. In the current study, a high-molecular-weight phostensin is identified by using immunoprecipitationin combination with a proteomic approach. This new species of phostensin is also encoded by KIAA1949 and consists of 613 Amino acids with an apparent molecular weight of 110 kDa on SDS-PAGE. The low-molecular-weight and high-molecular-weight phostensins were named as phostensin-α and phostensin-β, respectively. Although phostensin-α is the C-terminal region of phostensin-β, it is not degraded from phostensin-β. Phostensin-β is capable of associating with PP1 and actin filaments, and is present in many cell lines.