EF-1-beta and EF-1-delta stimulate the exchange of GDP bound to EF-1-alpha to GTP. EF-1 is composed of 4 subunits: alpha, beta, delta, and gamma (By similarity). Interacts with actin. Found in cortical and hyaline cytoplasm. Expressed during the vegetative growth phase, followed by marked decrease in response to cell differentiation induced by starvation. Belongs to the EF-1-beta/EF-1-delta family.