04. Cell Polarity
Ruth N. Collins, Molecular Medicine, and her graduate students, setting out to study how yeast establishes cell polarity, discovered a gene, E1p1, that is key in determining the structural and functional asymmetry of cells, or cell polarity. E1p1 is critical in regulating cell polarity, such as directing growth to the tip of a cell so that a daughter cell can bud off to divide. The discovery provides needed insight into the pathogenesis of familial dysautonomia (FD), a disease of nerve cell failures. FD is manifested soon after birth and results in a life span of less than 30 years. It is caused by a genetic defect in a protein that is the human counterpart to the E1p1 gene in yeast. The disease may arise from a lack of fully developed neurons, which must direct new growth to a tip of the cell in order to make synapses. Collins’ discovery gives researchers new insight into basic mechanisms of cell growth and differentiation, with implications for other disease such as cancer. Just as polarity is important for normal cell function, loss of polarity—reversal of the molecular pathway that creates cell polarity—is one of the early steps in the progression to uncontrolled cell proliferation.