Fifteen years of prothymosin alpha:: contradictory past and new horizons

Prothymosin alpha (ProT alpha) is a highly acidic and small protein of only 111 amino acids with an unusual primary structure. One would expected it to play an essential role in the organism, as it has a wide distribution and is high conserved among mammals, yet its exact function remains elusive. Despite the number of effects described for ProT alpha, intracellular and extracellular, none are accepted as its physiological role. Furthermore, many other aspects of its biology still remain obscure. In this review, we discuss the structural properties, location, gene family, functions and immunomodulatory activities of and cellular receptors for ProT alpha. These topics are addressed in an attempt to reconcile opposing outlooks while emphasizing those points where scant investigations do exist. We have also re-evaluated some previous results in light of the structural properties of ProT alpha and have found that molecular mimetism could be the underlying basis. This molecular mimicry hypothesis provides a clue that must nor be overlooked for a realistic appraisal of future results. (C) 2000 Elsevier Science Inc. All rights reserved.