WASp Homology domain 1 (WH1) domain. WASP is the protein that is defective in Wiskott-Aldrich syndrome (WAS). The majority of point mutations occur within the amino- terminal WH1 domain. The metabotropic glutamate receptors mGluR1alpha and mGluR5 bind a protein called homer, which is a WH1 domain homologue [2]. A subset of WH1 domains has been termed a "EVH1" domain [3] and appear to bind a polyproline motif.

1: Wiskott-Aldrich syndrome protein, a novel effector for the GTPase CDC42Hs, is implicated in actin polymerization. Symons M, Derry JM, Karlak B, Jiang S, Lemahieu V, Mccormick F, Francke U, Abo A; Cell 1996;84:723-734. PMID:8625410

2: Identification of homer as a homologue of the Wiskott-Aldrich syndrome protein suggests a receptor-binding function for WH1 domains Ponting CP, Phillips C; J Mol Med. 1997;75:769-771. PMID:9428607

3: A novel proline-rich motif present in ActA of Listeria monocytogenes and cytoskeletal proteins is the ligand for the EVH1 domain, a protein module present in the Enas/VASP family. Niebuhr K, Ebel F, Frank R, Reinhard M, Domann E, Carl UD, Walter U, Gertler FB, Wehland J, Chakraborty T; EMBO J 1997;16:5433-5444. PMID:9312002