Opposing effects of inositol hexakisphosphate on rod arrestin and arrestin2 self-association

Biochemistry. 2008 Jan 22;47(3):1070-5. doi: 10.1021/bi7021359. Epub 2007 Dec 28.


The robust cooperative formation of rod arrestin tetramers has been well-established, whereas the ability of other members of the arrestin family to self-associate remains controversial. Here, we used purified arrestins and multi-angle light scattering to quantitatively compare the propensity of the four mammalian arrestin subtypes to self-associate. Both non-visual and cone arrestins only form oligomers at very high non-physiological concentrations. However, inositol hexakisphosphate (IP6), a fairly abundant form of inositol in the cytoplasm, greatly facilitates self-association of arrestin2. Arrestin2 self-association equilibrium constants in the presence of 100 microM IP6 suggest that an appreciable proportion could exist in an oligomeric state but only in intracellular compartments where its concentration is 5-10-fold higher than average. In contrast to arrestin2, IP6 inhibits self-association of rod arrestin, indicating that the structure of these two tetramers in solution is likely different.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arrestin / chemistry*
  • Arrestin / metabolism
  • Arrestins / chemistry*
  • Arrestins / metabolism
  • Cattle
  • Chromatography, Gel
  • Dimerization
  • Humans
  • Lasers
  • Light
  • Molecular Weight
  • Phytic Acid / chemistry*
  • Phytic Acid / metabolism
  • Phytic Acid / pharmacology
  • Protein Binding / drug effects
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Scattering, Radiation
  • beta-Arrestins


  • Arrestin
  • Arrestins
  • Recombinant Proteins
  • arrestin3
  • beta-Arrestins
  • Phytic Acid