Checkpoints for vesicular traffic?

During interphase the transport of material between different intracellular organelles requires accurate regulation of fusiogenic domains. Recent stud ies on hepatic endosomes indicated that compartmentalized Cdk2 - cyclin E c omplexes act by braking fusion events. These Cdk2 complexes integrate tyros ine phosphorylation and dephosphory lation inputs, resulting in the control of the number of rounds of fusion at discrete domains. This leads to chang es in the intracellular location of internalized receptors and ultimately t heir biological response.