MICROTUBULE-DEPENDENT VESICLE TRANSPORT - MODULATION OF CHANNEL AND TRANSPORTER ACTIVITY IN LIVER AND KIDNEY

Microtubule-based vesicle transport driven by kinesin and cytoplasmic dynein motor proteins facilitates several membrane-trafficking steps i ncluding elements of endocytosis and exocytosis in many different cell types. Most early studies on the role of microtubule-dependent vesicl e transport in membrane trafficking focused either on neurons or on si mple cell lines. More recently, other work has considered the role of microtubule-based vesicle transport in other physiological systems, in cluding kidney and liver. Investigation of the role of microtubule-bas ed vesicle transport in membrane trafficking in cells of the kidney an d liver suggests a major role for microtubule-based vesicle transport in the rapid and directed movement of ion channels and transporters to and from the apical plasma membranes, events essential for kidney and liver function and homeostasis. This review discusses the evidence su pporting a role for microtubule based vesicle transport and the motor proteins, kinesin and cytoplasmic dynein, in different aspects of memb rane trafficking in cells of the kidney and liver, with emphasis on th ose functions such as maintenance of ion channel and transporter compo sition in apical membranes that are specialized functions of these org ans. Evidence that defects in microtubule-based transport contribute t o diseases of the kidney and liver is also discussed.