The ankyrin-binding domain of CD44s is involved in regulating hyaluronic acid-mediated functions and prostate tumor cell transformation

Cell Motil Cytoskeleton. 1998;39(3):209-22. doi: 10.1002/(SICI)1097-0169(1998)39:3<209::AID-CM4>3.0.CO;2-#.

Abstract

CD44 isoforms, such as CD44s (the standard form), contain at least one ankyrin-binding site within the 70-amino acid (aa) cytoplasmic domain and several hyaluronic acid (HA)-binding sites within the extracellular domain. To study the role of CD44s-ankyrin interaction in regulating human prostate tumor cells, we have constructed several CD44s cytoplasmic deletion mutants that lack the ankyrin-binding site(s). These truncated cDNAs were stably transfected into CD44-negative human prostate tumor cells (LNCaP). Our results indicate that a critical region of 15-amino acids (aa) between aa 304 and aa 318 of CD44s is required for ankyrin binding. Biochemical analyses, using competition binding assays with a synthetic peptide containing the 15 aa between aa 304 and aa 318 (NSGNGAVEDRKPSGL), further support the conclusion that this region contains the ankyrin-binding domain of CD44s. Deletion of this 15-aa ankyrin-binding sequence from CD44s results in a drastic reduction of HA-mediated binding/cell adhesion, Src p60 kinase(s) interaction and anchorage-independent growth in soft agar. These findings suggest that the binding of cytoskeletal proteins, such as ankyrin, to the cytoplasmic domain of CD44s plays a pivotal role in regulating HA-mediated functions as well as Src kinase activity and prostate tumor cell transformation.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Ankyrins / metabolism*
  • Carrier Proteins / metabolism
  • Cell Adhesion / physiology
  • Cell Division
  • Cell Transformation, Neoplastic*
  • DNA, Complementary
  • Humans
  • Hyaluronan Receptors / chemistry
  • Hyaluronan Receptors / genetics
  • Hyaluronan Receptors / metabolism*
  • Hyaluronic Acid / metabolism*
  • Male
  • Microfilament Proteins / metabolism
  • Molecular Sequence Data
  • Peptides / chemical synthesis
  • Peptides / metabolism
  • Prostatic Neoplasms / physiopathology*
  • Protein Binding
  • Proto-Oncogene Proteins pp60(c-src) / metabolism
  • Recombinant Fusion Proteins
  • Sequence Deletion
  • Spectrin / metabolism
  • Tumor Cells, Cultured

Substances

  • Ankyrins
  • Carrier Proteins
  • DNA, Complementary
  • Hyaluronan Receptors
  • Microfilament Proteins
  • Peptides
  • Recombinant Fusion Proteins
  • fodrin
  • Spectrin
  • Hyaluronic Acid
  • Proto-Oncogene Proteins pp60(c-src)