The association of the C-terminal region of beta I sigma II spectrin to brain membranes is mediated by a PH domain, does not require membrane proteins, and coincides with a inositol-1,4,5 triphosphate binding site
Wang, D.S.; Shaw, G.
Biochemical and Biophysical Research Communications 217(2): 608-615
1995
ISSN/ISBN: 0006-291X PMID: 7503742 Document Number: 453899
The beta spectrin genes each produce two alternate transcripts the longer of which has a apprx 210 amino acid C-terminal extension including a pleckstrin homology (PH) domain and also an uncharacterized membrane binding site. GST constructs including the entire or the N-terminal segment of the BI-SIGMA-II spectrin PH domain bind to crude and extracted brain membranes, to protein free brain lipid and to vesicles containing phosphatidylinositol-4,5-bisphosphate. This PH domain also binds radiolabelled inositol-1,4,5-trisphosphate (IP3) and preincubation with IP3 inhibits binding to extracted brain membranes. We conclude that membrane binding of the beta-I-SIGMA-II spectrin C-terminal region is by means of a direct interaction between the N-terminal region of the PH domain and membrane lipids and does not require membrane protein. The PH domain of the 8-adrenergic receptor kinase showed different binding properties in every assay employed. showing that different PH domains may have different membrane binding specificity.