“…ARF proteins are small molecular weight GTPases that were originally isolated from cell extracts as in vitro allosteric activators of CTA1 (Kahn and Gilman, 1984; 1986; Tsai et al ., 1987; 1988). There are six members of the ARF family grouped in three classes, and each class can activate CTA1 (Price et al ., ; Welsh et al ., ; Moss and Vaughan, ). ARF6 can bind to CTA1 over a range of temperatures in either the absence or the presence of GTP (Pande et al ., ), but only ARF/GTP can stimulate the ADP‐ribosyltransferase activity of CTA1 (Kahn and Gilman, 1984; 1986; Tsai et al ., ; Bobak et al ., ; Price et al ., ).…”