A preview of the emerging health care companies profiled in the current issue of Start-Up. This month's profile group, G-Protein Coupled Receptors, features profiles of Aptus Genomics Inc., Axovan Ltd., Norak Biosciences Inc. and 7TM Pharma. Plus these Selected Start-Ups across Health Care: ALung Technologies Inc., CancerVax Corp., MedExact Inc. and nanotype GMBH.

Researchers haven't yet been able to overcome the challenge of isolating and purifying GPCRs from their membrane in a functionally useful form, so it has been difficult to determine their structures, as a starting point for drug discovery. Researchers have, however, developed indirect ways of detecting whether particular compounds activate GPCRs, by measuring the effects of activation. The presence of certain secondary messengers within the cell, for example, calcium or cyclic AMP (cAMP), is a telltale sign that compounds have interacted with GPCRs. Aptus Genomics has applied for a patent for a high-throughput drug screening method for GPCRs that signal through cAMP.

It has always been popular to start companies around families and subfamilies of targets, banking on the similarity among the receptors to speed drug discovery. But the idea largely hasn't panned out, in part because of the new target risk--sometimes they're not pharmaceutically relevant and sometimes they resist the available chemistries. That's why G-protein coupled receptors (GPCRs) have been so important: they're clearly relevant (many, perhaps most, blockbusters come from this class of receptor) and their unique structure makes them both relatively easy to hit with ligands and likely to do something when hit. But the same structural advantages turn into scientific disadvantages for researchers: they resist screening and other techniques of modern drug discovery. We explore some of the newest approaches to mining this rich vein of opportunity.

In Vivo summarizes the technology of several recently founded companies: Aptus Genomics Inc. is developing a platform to identify, qualify, and patent human cell surface receptor genes. Raven Biotechnologies Inc. spin-off bioMosaic Systems Inc. will develop Raven's CellArray cell-based high-throughput screening system. IntelliServices Inc. is building a suite of ASP-based software solutions for physicians. Spine Wave Inc. will develop and commercialize a minimally-invasive method for spinal disc repair. 20/20 Gene Systems Inc. is building protein analysis tools for determining the molecular fingerprint of a patient sample and comparing it to archived information from a larger patient population. Xcel Pharmaceuticals Inc. will in-license pharmaceuticals for niche therapeutic markets, initially focusing on neurology.