2QNJ

Kinase and Ubiquitin-associated domains of MARK3/Par-1

Summary for 2QNJ

• Entry DOI: 10.2210/pdb2qnj/pdb
• Descriptor: MAP/microtubule affinity-regulating kinase 3 (2 entities in total)
• Functional Keywords: serine/threonine protein kinase, ubiquitin-associated domain, mark, par-1, transferase
• Biological source: Homo sapiens (human)
• Cellular location: Cell membrane ; Peripheral membrane protein : P27448
• Total number of polymer chains: 2
• Total formula weight: 75337.13

Authors

Murphy, J.M.,Ceccarelli, D.F.J.,Sicheri, F.,Pawson, T. (deposition date: 2007-07-18, release date: 2007-09-04, Last modification date: 2024-10-30)

Primary citation

Murphy, J.M.,Korzhnev, D.M.,Ceccarelli, D.F.,Briant, D.J.,Zarrine-Afsar, A.,Sicheri, F.,Kay, L.E.,Pawson, T.
Conformational instability of the MARK3 UBA domain compromises ubiquitin recognition and promotes interaction with the adjacent kinase domain
Proc.Natl.Acad.Sci.Usa, 104:14336-14341, 2007

PubMed Abstract: The Par-1/MARK protein kinases play a pivotal role in establishing cellular polarity. This family of kinases contains a unique domain architecture, in which a ubiquitin-associated (UBA) domain is located C-terminal to the kinase domain. We have used a combination of x-ray crystallography and NMR dynamics experiments to understand the interaction of the human (h) MARK3 UBA domain with the adjacent kinase domain as compared with ubiquitin. The x-ray crystal structure of the linked hMARK3 kinase and UBA domains establishes that the UBA domain forms a stable intramolecular interaction with the N-terminal lobe of the kinase domain. However, solution-state NMR studies of the isolated UBA domain indicate that it is highly dynamic, undergoing conformational transitions that can be explained by a folding-unfolding equilibrium. NMR titration experiments indicated that the hMARK3 UBA domain has a detectable but extremely weak affinity for mono ubiquitin, which suggests that conformational instability of the isolated hMARK3 UBA domain attenuates binding to ubiquitin despite the presence of residues typically involved in ubiquitin recognition. Our data identify a molecular mechanism through which the hMARK3 UBA domain has evolved to bind the kinase domain, in a fashion that stabilizes an open conformation of the N- and C-terminal lobes, at the expense of its capacity to engage ubiquitin. These results may be relevant more generally to the 30% of UBA domains that lack significant ubiquitin-binding activity, and they suggest a unique mechanism by which interaction domains may evolve new binding properties.

PubMed: 17726107
DOI: 10.1073/pnas.0703012104

Experimental method

X-RAY DIFFRACTION (2.7 Å)