3mfr
From Proteopedia
CASK-4M CaM Kinase Domain, native
Structural highlights
Disease[CSKP_HUMAN] Defects in CASK are the cause of mental retardation and microcephaly with pontine and cerebellar hypoplasia (MICPCH) [MIM:300749]. A disorder characterized by significantly below average general intellectual functioning associated with impairments in adaptative behavior and manifested during the developmental period. Patients with mental retardation X-linked CASK-related can manifest a severe phenotype consisting of severe intellectual deficit, congenital or postnatal microcephaly, disproportionate brainstem and cerebellar hypoplasia. A milder phenotype consists of mental retardation alone or associated with nystagmus.[1] Defects in CASK are the cause of FG syndrome type 4 (FGS4) [MIM:300422]. FG syndrome (FGS) is an X-linked disorder characterized by mental retardation, relative macrocephaly, hypotonia and constipation.[2] Function[CSKP_HUMAN] Multidomain scaffolding protein with a role in synaptic transmembrane protein anchoring and ion channel trafficking. Contributes to neural development and regulation of gene expression via interaction with the transcription factor TRB1. Binds to cell-surface proteins, including amyloid precursor protein, neurexins and syndecans. May mediate a link between the extracellular matrix and the actin cytoskeleton via its interaction with syndecan and with the actin/spectrin-binding protein 4.1. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAll known protein kinases, except CASK [calcium/calmodulin (CaM)-activated serine-threonine kinase], require magnesium ions (Mg(2+)) to stimulate the transfer of a phosphate from adenosine 5'-triphosphate (ATP) to a protein substrate. The CaMK (calcium/calmodulin-dependent kinase) domain of CASK shows activity in the absence of Mg(2+); indeed, it is inhibited by divalent ions including Mg(2+). Here, we converted the Mg(2+)-inhibited wild-type CASK kinase (CASK(WT)) into a Mg(2+)-stimulated kinase (CASK(4M)) by substituting four residues within the ATP-binding pocket. Crystal structures of CASK(4M) with and without bound nucleotide and Mn(2+), together with kinetic analyses, demonstrated that Mg(2+) accelerates catalysis of CASK(4M) by stabilizing the transition state, enhancing the leaving group properties of adenosine 5'-diphosphate, and indirectly shifting the position of the gamma-phosphate of ATP. Phylogenetic analysis revealed that the four residues conferring Mg(2+)-mediated stimulation were substituted from CASK during early animal evolution, converting a primordial, Mg(2+)-coordinating form of CASK into a Mg(2+)-inhibited kinase. This emergence of Mg(2+) sensitivity (inhibition by Mg(2+)) conferred regulation of CASK activity by divalent cations, in parallel with the evolution of the animal nervous systems. Evolution of CASK into a Mg2+-sensitive kinase.,Mukherjee K, Sharma M, Jahn R, Wahl MC, Sudhof TC Sci Signal. 2010 Apr 27;3(119):ra33. PMID:20424264[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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