A conserved salt bridge in the G loop of multiple protein kinases is important for catalysis and for in vivo Lyn function.
The glycine-rich G loop controls ATP binding and phosphate transfer in protein kinases. Here we show that the functions of Src family and Abl protein tyrosine kinases require an electrostatic interaction between oppositely charged amino acids within their G loops that is conserved in multiple other phylogenetically distinct protein kinases, from plants to humans. By limiting G loop flexibility, it controls ATP binding, catalysis, and inhibition by ATP-competitive compounds such as Imatinib. In WeeB mice, mutational disruption of the interaction results in expression of a Lyn protein with reduced catalytic activity, and in perturbed B cell receptor signaling. Like Lyn(-/-) mice, WeeB mice show profound defects in B cell development and function and succumb to autoimmune glomerulonephritis. This demonstrates the physiological importance of the conserved G loop salt bridge and at the same time distinguishes the in vivo requirement for the Lyn kinase activity from other potential functions of the protein.
Barouch-Bentov
Rina
R
Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA.
Che
Jianwei
J
Lee
Christian C
CC
Yang
Yating
Y
Herman
Ann
A
Jia
Yong
Y
Velentza
Anastasia
A
Watson
James
J
Sternberg
Luise
L
Kim
Sunjun
S
Ziaee
Niusha
N
Miller
Andrew
A
Jackson
Carie
C
Fujimoto
Manabu
M
Young
Mike
M
Batalov
Serge
S
Liu
Yi
Y
Warmuth
Markus
M
Wiltshire
Tim
T
Cooke
Michael P
MP
Sauer
Karsten
K
D000595:Amino Acid Sequence; D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology / Q000473:pathology; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D001549:Benzamides; D055162:Biocatalysis / Q000187:drug effects; D017124:Conserved Sequence; D019008:Drug Resistance, Neoplasm; D004789:Enzyme Activation / Q000187:drug effects; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism; D000068877:Imatinib Mesylate; D051379:Mice; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D010879:Piperazines / Q000494:pharmacology; D011494:Protein Kinases / Q000737:chemistry*; D055550:Protein Stability / Q000187:drug effects; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011743:Pyrimidines / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D055672:Static Electricity; D019061:src-Family Kinases / Q000737:chemistry* / Q000378:metabolism*
D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D011947:Receptors, Antigen, B-Cell; D000068877:Imatinib Mesylate; D011494:Protein Kinases; D016044:Fusion Proteins, bcr-abl; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases