Enables heat shock protein binding activity. Involved in leukocyte tethering or rolling and positive regulation of T cell migration. Acts upstream of or within several processes, including positive regulation of macromolecule metabolic process; regulation of T cell activation; and regulation of defense response. Located in basement membrane; external side of plasma membrane; and uropod. Is integral component of plasma membrane. Orthologous to human SPN (sialophorin). [provided by Alliance of Genome Resources, Apr 2022]