In www.biorxiv.org/content/10.6... Yean Ming Chew & I show that mutating the interPF interface in human MTs can allow them to assemble in GDP. We propose that tubulin molecules are captured indiscriminately at MT tips but then retained only if they can bind stably to a lateral nearest-neighbour.

After trenchant reviewing, Karnawat et al is out, showing that ATPγS causes single kinesin molecules to pause under load in an Await-Isomerisation (AI) state that leaks hand-over-hand backsteps. In ATP we think this state serves to couple forward stepping to hydrolysis www.nature.com/articles/s41...

Have to feel for the grey eduWOSM. It's just so .. grey ..

Nick showing Ron Vale the eduWOSM.

In BIORXIV/2025/651652, we use ATPγS to reveal a previously-occult kinesin state. In the Await-Isomerisation (AI) state, ATP is bound but NL docking and hydrolysis are inhibited. ATPγS overstabilises the AI state, producing a characteristic signature of load-independent 8 nm tethered backslips:

Nick has been in Rennes, helping Romain Gibeaux install a WOSM-TIRF. Big happiness!

Prakash et al (doi.org/10.1101/2025...), emerging from a happy & ongoing multilab collaboration, shows that a mix of human α1β3 and α1β4 tubulins assembles in vitro into segmented microtubules in which the segments have different protofilament numbers, and are recognized by different MAPS.

Tubulin isotypes polymerise into sectioned microtubules that locally regulate protein binding

Microtubules assemble from tubulin heterodimers composed of conserved α- and β- tubulins. In many species, including humans, tubulins are expressed from multiple genes. While the resulting tubulin iso...

doi.org

Yean Ming Chew and I wrote doi.org/10.1042/BST2... about MT lattice switching. We discuss evidence that protofilament-level structural switching is ancient and fundamental and conserved; and that tubulation creates new allosteric interfaces that operate on essentially the same structural switch.