Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 10: Posters - Single Molecule Biophysics
BP 10.9: Poster
Montag, 20. März 2017, 17:30–19:30, P3
Recombinant mammalian kinesin-3, KIF16B, is not autoinhibited and moderately processive by itself — •Rahul Grover1,2, Raluca Groza1, Tim Rehfeldt1, and Stefan Diez1,2 — 1B CUBE & cfaed, TU Dresden, Germany — 2MPI-CBG, Dresden, Germany
KIF16B, a kinesin-3 family motor, is involved in the transport and localization of early endosomes. It exhibits a lipid-binding PX-domain, through which it directly binds to PI(3)P-containing vesicles. Recent in-vivo studies on KIF16B have proposed contradictory mechanisms for its activity and transport properties. One study proposed that KIF16B is a monomer and dimerizes only when bound to a membranous cargo, upon which it becomes activated and super-processive (run length > 10 um). In contrast, another study proposed that KIF16B is autoinhibhited by its stalk domain in an ATP-dependent manner without any influence of the presence of membranous cargo or PX-domains. Thus, studying single KIF16B motors in the complex environment of a cell appears to be difficult, resulting in inconsistent postulations about its functional principles. To understand the molecular mechanism of KIF16B we carried out in-vitro assays with purified components. We expressed full-length KIF16B motors labeled with GFP and performed stepping motility assays as well as photobleaching analysis. We found that single molecules of KIF16B are active, dimeric and moderately processive (run length < 2 um). Our results suggest that other auxillary proteins (e.g. Rab-family proteins) can be involved in regulating the activity of KIF16B in cells.