The identification of a second actin-binding region in spinophilin/neurabin II.
Spinophilin/neurabin II is an actin-associated scaffolding protein enriched in the dendritic spines of neurons. Previously, the actin-binding domain (ABD) of spinophilin was localized to a domain between amino acids (aa) 1 and 154. In a mass spectrometry screen for spinophilin-binding proteins, we have identified an additional actin-binding region between aa 151 and 282. F-actin co-sedimentation and GST affinity chromotography experiments further substantiate this result. Phalloidin staining of Rat2 fibroblasts transiently expressing GFP-spinophilin deletion constructs indicates co-localization with a subset of actin. Regions of spinophilin that lack the revised ABD (aa 1-230) do not co-localize with phalloidin-labeled actin, suggesting that the actin-binding domain contributes to directing the subcellular distribution of spinophilin. Targeting experiments using primary hippocampal cultures indicate that only the first actin-binding site contributes to dendritic spine localization. The second ABD targets to spines inefficiently and thus may interact with and affect actin filaments in a different manner than the first ABD.
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Related Subject Headings
- Sequence Homology, Amino Acid
- Recombinant Fusion Proteins
- Rats
- Protein Structure, Tertiary
- Protein Binding
- Neurology & Neurosurgery
- Nerve Tissue Proteins
- Molecular Sequence Data
- Microfilament Proteins
- Humans
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Sequence Homology, Amino Acid
- Recombinant Fusion Proteins
- Rats
- Protein Structure, Tertiary
- Protein Binding
- Neurology & Neurosurgery
- Nerve Tissue Proteins
- Molecular Sequence Data
- Microfilament Proteins
- Humans