Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
United States: Cold Spring Harbor Laboratory Press
Erscheinungsjahr
2021
Link zum Volltext
Quelle
MEDLINE
Beschreibungen/Notizen
Kinesin-1 carries cargos including proteins, RNAs, vesicles, and pathogens over long distances within cells. The mechanochemical cycle of kinesins is well described, but how they establish cargo specificity is not fully understood. Transport of
mRNA to the posterior pole of the
oocyte is mediated by
kinesin-1, also called kinesin heavy chain (Khc), and a putative cargo adaptor, the atypical tropomyosin,
Tm1. How the proteins cooperate in mRNA transport is unknown. Here, we present the high-resolution crystal structure of a Khc-
Tm1 complex. The proteins form a tripartite coiled coil comprising two in-register Khc chains and one
Tm1 chain, in antiparallel orientation. We show that
Tm1 binds to an evolutionarily conserved cargo binding site on Khc, and mutational analysis confirms the importance of this interaction for mRNA transport in vivo. Furthermore, we demonstrate that Khc binds RNA directly and that it does so via its alternative cargo binding domain, which forms a positively charged joint surface with
Tm1, as well as through its adjacent auxiliary microtubule binding domain. Finally, we show that
Tm1 plays a stabilizing role in the interaction of Khc with RNA, which distinguishes
Tm1 from classical motor adaptors.