ABCMdb

PMID: 21594801

Csanady L, Vergani P, Gulyas-Kovacs A, Gadsby DC
Electrophysiological, biochemical, and bioinformatic methods for studying CFTR channel gating and its regulation.
Methods Mol Biol. 2011;741:443-69., [PubMed]

Sentences

No. Mutations Sentence Comment

31 ABCC7 p.Gly551Asp Moreover, deletion of the entire NBD2 (40, 41) or introduction of "constitutive" mutations (42), even the CF-causing mutation G551D (43), results in channels that gate regardless of the presence of ATP - but even this "spontaneous" activity remains strictly dependent on prior phosphorylation by PKA. Login to comment 70 ABCC7 p.Ser768Ala The presence of active endogenous phosphatases in excised patches even permits determination of PKA concentration dependence of CFTR channel activation, assayed as Po; enhanced sensitivity to PKA in Ser768Ala mutants compared to WT CFTR (36) confirmed the inhibitory influence of phosphoserine 768 concluded from measurements of sensitivity to the phosphodiesterase inhibitor IBMX in intact oocytes (46). Login to comment 71 ABCC7 p.Ser768Ala The enhanced sensitivity to phosphorylation resulted in substantial activation of Ser768Ala CFTR channels in resting oocytes, due to basal levels of PKA activity; phosphorylation of six Ser (including Ser768) in the R domains of WT CFTR channels in resting oocytes was confirmed by mass spectrometry (36). Login to comment 135 ABCC7 p.Glu1371Gln For instance, mutations might simultaneously alter the rates of both gating transitions by up to 1000-fold with no large effect on Po (e.g., E1371Q; (1)), emphasizing the importance of kinetic analysis for mechanistic understanding. Login to comment 187 ABCC7 p.Lys1250Ala This technique for estimating mean burst duration has been preferentially used for catalytic site mutants which abolish ATP hydrolysis at the composite NBD2 site (e.g., K1250A), or when non-hydrolyzable ATP analogs (e.g., AMP-PNP and pyrophosphate) are applied, because in either case burst durations are prolonged to several seconds or tens of seconds. Login to comment