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Cover  Little is known about how motor proteins are targeted to their specific membrane compartments. Four recent papers (Fukada et al. (2002), J. Biol. Chem. 277, 12432-12436; Nagashima et al. (2002), FEBS Letters 26023, 1-6; Strom et al. (2002), J. Biol. Chem. 277, 25423-25430; Wu et al. (2002), Nature Cell Biol. 4, 271-278) show that myosin Va, an actin-based vesicle motor, binds to one of its cargoes, the melanosome, by interacting with a receptor-protein complex containing Rab27a and melanophilin, a postulated Rab27a effector. Rab27a binds to the melanosome first and then recruits melanophilin, which in turn recruits myosin Va. Melanophilin creates this link by binding to Rab27a in a GTP-dependent fashion through its amino terminus, and to myosin Va through its carboxy terminus. Moreover, this latter interaction, like the ability of myosin Va to colocalize with melanosomes and influence their distribution in vivo (Huang et al. (1998), Genetics 148, 1963-1972; Wu et al. (2002), Mol. Biol. Cell 13, 1735-1749), is dependent on the presence of exon-F, an alternatively spliced exon in the myosin Va tail. Together, these results have provided the first molecular description of an organelle receptor for an actin-based motor, have illustrated how alternate exon usage can be used to specify cargo, and have further expanded the functional repertoire of Rab GTPases and their effectors. The cover shows a triple overlay of a mouse melanocyte that has been transfected with CFP-tagged Rab27a (inset, lower panel) and GFP-tagged melanophilin (inset, middle panel) and then stained for endogenous myosin VA (inset, upper panel). White indicates where all three proteins overlap. John Hammer