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

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.

• Authors: D Zhu, L Y Bourguignon
• Journal: Cell motility and the cytoskeleton (Cell Motil Cytoskeleton) Vol. 39 Issue 3 Pg. 209-22 ( 1998) ISSN: 0886-1544 [Print] United States
• PMID: 9519902 (Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

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

Topics

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