September 12, 2007 Time: 00:29am t1-v1.1 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Urinary Lipocalins in Rodenta: is there a Generic Model? Robert J. Beynon, Jane L. Hurst, Michael J. Turton, Duncan H. L. Robertson, Stuart D. Armstrong, Sarah A. Cheetham, Deborah Simpson, Alan MacNicoll, and Richard E. Humphries Abstract It is increasingly clear that mediation of chemical signals is not the exclu- sive domain of low molecular volatile or water soluble metabolites. Pheromone binding proteins play an important role in mediating the activity of low molec- ular weight compounds, while proteins and peptides can also act as information molecules in their own right. Understanding of the role played by proteins in scents has been derived largely from the study of Major Urinary Proteins (MUPs) in the mouse (Mus musculus domesticus) and the rat (Rattus norvegicus). As part of an ongoing programme to explore the diversity and complexity of urinary pro- teins in rodents, we have applied a proteomics-based approach to the analysis of urinary proteins from a wider range of rodents. These data suggest that many species express proteins in their urine that are structurally similar to the MUPs, although there is considerable diversity in concentration, in sexual dimorphism and in polymorphic complexity. This is likely to reflect a high degree of species- specificity in communication and the information that these proteins provide in scent signals. 1 Introduction Early views of pheromone chemistry were shaped in part by precedents derived from the insect world. Thus, semiochemicals were considered to be low molecu- lar weight, volatile molecules that were transmitted through the atmosphere from sender to receiver. The (somewhat alliterative) “simple, single signal” model has served well, but in higher animals it is necessary to invoke additional complexity. First, it becomes more critical that the receiver of the signal is able to identify the individual that transmitted the signal together with its status. The ability to recognise individual conspecifics and/or kin and associate this with information about that individual’s status and behaviour is likely to be critical to most social interactions within vertebrate species, including competitor assessment, mate assessment, and Robert J. Beynon University of Liverpool, Proteomics & Functional Genomics Group r.beynon@liv.ac.uk J.L. Hurst et al., Chemical Signals in Vertebrates 11. 37 C  Springer 2008