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Figure 3. Schematic illustrating targeting of multiple SH3 domain proteins to BK channels, including the adapter protein cortactin that links BK channels to the actin cytoskeleton. Schematic of a single pore-forming subunit of the BK channel illustrating the intracellular proline-rich domain (PRD) that contains SH3 domain binding motifs SBM1 and SBM2. The adapter protein cortactin contains an SH3 domain that interacts with the BK channel and domains that interact directly with the cortical actin cytoskeleton. A diverse array of other SH3 domain proteins, including adapter proteins and proteins involved in structural organization and cell signaling, interact with the PRD. As BK channels are formed by assembly of four pore-forming subunits, multiple distinct SH3 domain proteins may be able to interact with the same BK channel.
