The polarity of microtubules is a feature that is highly important for subcellular organization and directionality of intracellular transport. Similarly, the different dynamic properties of the plus and minus ends of microtubules play a vital role in the organization and functions of microtubules. Some proteins, called microtubule plus-end-tracking proteins (+TIPs), particularly associate with the plus ends of microtubules. Many of these are known to regulate the dynamics, interactions and functions of microtubules. Recently, also microtubule minus-end-targeting proteins (-TIPs), that particularly associate with free minus ends of non-centrosomal microtubules, have been identified.
Staining of microtubule ends gives rise to a sprinkled pattern, in which only the outermost tip of the plus end of each microtubule, or sometimes the minus end of non-centrosomal microtubules, is stained.
Read more about the proteome of microtubule ends as a substructure of microtubules