Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Binding of PP1c to scaffold proteins may modulate ion channel activity (44), while at neuronal synapses, neurabins I and II (also termed spinophilin) localize PP1c to the actin cytoskeleton at the plasma membrane (1, 32, 33, 37).
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