LYN and plasma cell myeloma: Some signaling molecules, such as IL-6R, gp130 and Lyn, are localized in the raft fraction before and/or after cytokine stimulation [17,27], while other molecules, such as CD45, depart from rafts after CD3 stimulation in T cells [28] or move into raft fractions upon BCR engagement in B cells [29] and IL-6 stimulation in myeloma cells [17], suggesting the important regulative role of lipid raft in signaling transduction.