Constitutive Activity in an Ancestral Form of Abl Tyrosine Kinase.

摘要: The c-abl proto-oncogene encodes a nonreceptor tyrosine kinase that is found in all metazoans, and ubiquitously expressed mammalian tissues. Abl plays important roles the regulation of cell physiology. Abl-like kinases have been identified genomes unicellular choanoflagellates, closest relatives to Metazoa, related organisms. Here, we carried out first characterization premetazoan kinase, MbAbl2, from choanoflagellate Monosiga brevicollis. enzyme possesses SH3, SH2, domains similar arrangement its counterparts, an active kinase. MbAbl2 lacks N-terminal myristoylation cap sequences are critical regulators activity, show constitutively active. When cells, strongly phosphorylates cellular proteins on tyrosine, transforms cells much more potently than Thus, appears lack autoinhibitory mechanism tightly constrains activity kinases, suggesting this regulatory apparatus arose recently metazoan evolution.