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:SNX27 however, possesses a unique PDZ domain involved in alternative cargo trafficking (Cai et al., 2011; Gallon et al., 2014; Lauffer et al., 2010; Lunn et al., 2007; Steinberg et al., 2013; Temkin et al., 2011; Valdes et al., 2011; Wang et al., 2013), and our results now suggest an additional unique property of this protein with respect to lipid headgroup association, interacting with PtdInsP species not bound by the other family members.
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