SUD and PABP do not compete with each other for interacting with Paip1. (A) Excess expression of SUD-RFP does not impair the split-YFP signal between PABP and Paip1 (lower images), compared to the control (upper images). (B) Co-expression of excess RFP-PABP does not result in an impaired interaction between Paip1 and SUD either. RFP: red fluorescent protein. Scale bars represent 50 µM. 