By cloning a murine homologue to a yeast protein involved in endocytosis and characterizing its intracellular localization, Engqvist-Goldstein et al. (page 1503) have begun to uncover the molecular machinery linking endocytosis to the actin cytoskeleton in mammalian cells. Though the functional connection between the actin cytoskeleton and endocytosis has been firmly established in yeast, the endocytic role of actin has not been determined as clearly in mammalian cells.
After identifying a homologue to the yeast Sla2 gene in a murine EST database, Engqvist-Goldstein and colleagues cloned the corresponding cDNA and characterized the mouse protein, designated mHip1R. Sequence alignments and secondary structure predictions verify that mHip1R is a member of the Sla2 protein family, of which the yeast protein is suggested to link that actin cytoskeleton to endocytosis, and a human member binds to huntingtin, the protein that is mutated...
