Constitutive transport between the trans-Golgi network and the plasma membrane according to the maturation model. A hypothesis

Here we examine the application of the cisternal/carrier maturation model to describe transport of cargo proteins from the Golgi apparatus to the plasma membrane. Interpretation of the available evidence in the light of carrier maturation suggests that the transport intermediates between these stations are large pleiomorphic carriers formed by maturation of the trans-Golgi compartment, rather than vesicles, as would be postulated by the vesicular shuttle model. Mature carriers move along microtubules towards the plasma membrane via a microtubule/(kinesin)-based motor system. The maturation and vesicular transport models are compared in terms of consistency with the available literature.