GluA1o than observed in previous experiments (Fig. 1). Within the time frame of 16 hrs, we did neither observe changes in cell morphology nor a reduction in GluA1 total protein expression. As the amount of surface protein is not only determined by the rate of anterograde transport, but also by the rate of removal from the plasma membrane, we probed a possible role for CNIH-2 in GluA endocytosis. Blocking of clathrin-dependent endocytosis via expression of a dominant-negative mutant of dynamin-1 (K44A; [38]) increased GluA1o surface expression by a factor of 2.3 (n = 6; p<0.01) in the absence of CNIH-2 and by a factor of 2 (n = 6; p<0.001) in the presence of CNIH-2 (data not shown). However, the CNIH-2-mediated relative increase in GluA1o surface expression was not affected by inhibition of endocytosis (Fig. 3C).
