Microtubuleassociated

Microtubule-associated proteins (MAPs) are a diverse group of proteins that bind to microtubules and regulate their behavior. They influence microtubule stability, dynamics, organization, and interactions with motor proteins and other cellular structures. MAPs function across cellular contexts, coordinating cytoskeleton remodeling during cell division, intracellular transport, and neuronal development.

MAPs can be broadly grouped into structural MAPs, plus-end tracking proteins, severing factors, and microtubule polymerases. Structural MAPs such as tau, MAP2, and MAP4 coat the microtubule lattice to stabilize filaments and promote crosslinking. In neurons, tau stabilizes axonal microtubules while MAP2 is enriched in dendrites. Plus-end tracking proteins (+TIPs) like EB1 and EB3 associate with growing microtubule ends and recruit other factors to regulate growth and interactions with cellular structures. Motor-adaptor and cargo-connecting MAPs help couple microtubules to kinesin or dynein motors. Severing enzymes such as katanin and spastin cut microtubules to remodel networks, generating new ends for growth or disassembly. Polymerases, including XMAP215/Dis1/TOG family members, promote tubulin addition at the plus end to accelerate polymerization.

MAP function is tightly regulated by phosphorylation and other post-translational modifications, cellular context, and interactions with other proteins. Dysregulation of MAPs is linked to disease, notably tau in neurodegenerative disorders such as Alzheimer’s disease, and certain MAP mutations or dysregulations contribute to neurodevelopmental defects. In summary, microtubule-associated proteins coordinate the assembly, stability, and organization of the microtubule network and are essential for proper cellular function.