Vertebrate protein homologues of UNC-53 protein of C. elegans and nucleic acid sequences coding for said homologues or functional equivalents thereof are identified. The nucleic acid sequences in an appropriate vector are used to transfect or transform cells, tissues or organisms useful in identifying inhibitors or enhancers of the vertebrate homologue, or further proteins involved in the signal transduction pathway of which said vertebrate homologue is a component. Any of said inhibitors or enhancers identified can be included in a pharmaceutical composition or in the preparation of a medicament for treating conditions such as neurological diseases, acute traumatic injuries and to promote neuronal regeneration and inhibit metastasis or loss of contact inhibition.