14-3-3ɛ, a universal adaptor protein, could bind to the tail domain of Kinesin-2 motor subunit KIF3B

KIF3A/KIF3B/KAP complex is a subfamily of kinesin-2 proteins and is known to transport cargoes like N-cadherin, Rab4 vesicles, Par3-Par6-aPKC complex and intraflagellar proteins. The adaptor proteins to recruit the heterotrimeric kinesin-2 to its specific cargoes are not identified, and hence, not much is known about the mechanism for its cargo recognition and binding. The 14-3-3 family proteins form homo and heterodimers and bind to several types of receptors and protein kinases/phosphates to bring together a multiprotein complex regulating cell signalling. In this study, we show that one of the 14-3-3 isoforms,14-3-3ɛ, can bind to KIF3B in vitro. We mapped the 14-3-3ɛ binding site on the C-terminal tail domain of KIF3B with the help of acceptor photobleaching-Foster Resonance Energy Transfer and split-APEX2 assays. With this evidence, we propose for the first time that 14-3-3ɛ can be a potential adaptor for kinesin-2.