An isolated protein (I) comprising a 300 amino acid (aa) sequence (2), reproduced, and derivatives of (2) having substitutions, inversions, insertions or deletions of one or more aa (provided they retain the essential biological properties of (2)), are new. Independent claims are also included for the following: (a) nucleic acid (II) encoding (I) or proteins with at least 60% identity with (2); (b) recombinant nucleic acid construct containing (I) linked to a regulatory element; (c) a host organism transformed with (II) or the construct of (b); (d) transgenic animals containing a (non-)functional construct of (b); (e) antibodies (Ab) that react selectively with (I); and (f) a method for identifying (ant)agonists or ligands (A) of (I).
