Tubulin, a well-known component of the microtubule in the cytoskeleton, has an important role in the transport and positioning of mitochondria in a cell type dependent manner. This review describes different functional interactions of
tubulin with cellular
protein complexes and its functional interaction with the mitochondrial outer membrane.
Tubulin is present in oxidative as well as glycolytic type muscle cells, but the kinetics of the in vivo regulation of mitochondrial respiration in these muscle types is drastically different. The interaction between VDAC and
tubulin is probably influenced by such factors as isoformic patterns of VDAC and
tubulin, post-translational modifications of
tubulin and phosphorylation of VDAC. Important factor of the selective permeability of VDAC is the
mitochondrial creatine kinase pathway which is present in oxidative cells, but is inactive or missing in glycolytic muscle and
cancer cells. As the
tubulin-VDAC interaction reduces the permeability of the channel by
adenine nucleotides, energy transfer can then take place effectively only through the
mitochondrial creatine kinase/
phosphocreatine pathway. Therefore, closure of VDAC by
tubulin may be one of the reasons of apoptosis in cells without the
creatine kinase pathway. An important question in
tubulin regulated interactions is whether other
proteins are interacting with
tubulin. The functional interaction may be direct, through other
proteins like plectins, or influenced by simultaneous interaction of other complexes with VDAC.