Rice (Oryza sativa) contains a novel isoform of glutamate decarboxylase that lacks an authentic calmodulin-binding domain at the C-terminus

2001 ◽  
Vol 1522 (3) ◽  
pp. 143-150 ◽  
Author(s):  
Kazuhito Akama ◽  
Takashi Akihiro ◽  
Masato Kitagawa ◽  
Fumio Takaiwa
Keyword(s):  
Oryza Sativa ◽  
Glutamate Decarboxylase ◽  
Binding Domain ◽  
Calmodulin Binding ◽  
C Terminus

scholarly journals New Ca2+ pump isoforms generated by alternative splicing of rPMCA2 mRNA

1992 ◽  
Vol 283 (2) ◽  
pp. 355-359 ◽  
Author(s):  
H P Adamo ◽  
J T Penniston
Keyword(s):  
Amino Acids ◽  
Variable Region ◽  
Rat Plasma ◽  
Lipid Binding ◽  
Binding Domain ◽  
Kinase Substrate ◽  
Calmodulin Binding ◽  
Hypervariable Regions ◽  
C Terminus ◽  
Domain Insertion

Alternative splices capable of generating proteins with altered functions were found (by PCR) in isoform 2 of the rat plasma membrane Ca2+ pump. These splices were concentrated in two hypervariable regions. One of these regions, near the N-terminus and the lipid-binding region, could be altered by the insertion of either or both of inserts x and y. Insertion of both x and y would add 45 amino acids to the molecule. The y insert causes the appearance of a rather hydrophobic stretch of amino acids in the middle of a highly polar region. The second variable region begins in the middle of the calmodulin-binding domain. Insertion of 229 nucleotides at this point of the message converts the b form to the a form, which has an altered (and shorter) C-terminus. The calmodulin-binding domain of this shortened form has a less basic character, which would decrease the affinity for calmodulin. The b form of isoenzyme 2 contains relatively weak protein kinase A substrate sequences, such as KQNSS and KNNS. These sequences are eliminated in form a, and a strongly activated kinase substrate sequence, RRQSS, appears in a different place. Different tissues use different combinations of alternative splices, with heart and brain showing the greatest diversity.

scholarly journals Calmodulin is responsible for Ca2+-dependent regulation of TRPA1 Channels

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Raquibul Hasan ◽  
Alasdair T. S. Leeson-Payne ◽  
Jonathan H. Jaggar ◽  
Xuming Zhang
Keyword(s):  
Ion Channel ◽  
Binding Domain ◽  
Dependent Manner ◽  
Calmodulin Binding ◽  
Sensory Disorders ◽  
C Terminus

Abstract TRPA1 is a Ca2+-permeable ion channel involved in many sensory disorders such as pain, itch and neuropathy. Notably, the function of TRPA1 depends on Ca2+, with low Ca2+ potentiating and high Ca2+ inactivating TRPA1. However, it remains unknown how Ca2+ exerts such contrasting effects. Here, we show that Ca2+ regulates TRPA1 through calmodulin, which binds to TRPA1 in a Ca2+-dependent manner. Calmodulin binding enhanced TRPA1 sensitivity and Ca2+-evoked potentiation of TRPA1 at low Ca2+, but inhibited TRPA1 sensitivity and promoted TRPA1 desensitization at high Ca2+. Ca2+-dependent potentiation and inactivation of TRPA1 were selectively prevented by disrupting the interaction of the carboxy-lobe of calmodulin with a calmodulin-binding domain in the C-terminus of TRPA1. Calmodulin is thus a critical Ca2+ sensor enabling TRPA1 to respond to diverse Ca2+ signals distinctly.

scholarly journals Structure–function relationship of the human erythrocyte plasma membrane Ca2+-ATPase revealed by V8 protease treatment

1991 ◽  
Vol 279 (2) ◽  
pp. 537-544 ◽  
Author(s):  
K K W Wang ◽  
B D Roufogalis ◽  
T H Kuo
Keyword(s):  
Human Erythrocyte ◽  
Plasma Membranes ◽  
Catalytic Domain ◽  
Phosphorylation Site ◽  
Bovine Brain ◽  
Binding Domain ◽  
Aureus Strain ◽  
Fragmentation Pattern ◽  
Calmodulin Binding ◽  
C Terminus

Treatment of the solubilized and purified Ca(2+)-translocating ATPase (Ca(2+)-ATPase) (136 kDa) from human erythrocyte plasma membranes with endoproteinase Glu-C from Staphylococcus aureus strain V8 (V8 protease) yielded transient fragments of 96 kDa and 76 kDa and more stable fragments of 60 kDa and 37/36 kDa (doublet). The presence of calmodulin did not alter the fragmentation pattern. The 60 kDa fragment contains the protein kinase C (bovine brain) phosphorylation site(s), which we previously localized in the C-terminal region [Wang, Wright, Machan, Allen, Conigrave & Roufogalis (1991) J. Biol. Chem. 266, 9078-9085]. On the other hand, the 37/36 kDa fragments possess the ability to form an acyl-phosphate intermediate. Furthermore, the presence of the 60 kDa and 37/36 kDa fragments together results in expression of calmodulin-sensitive Ca(2+)-ATPase activity. However, further degradation of the 60 kDa fragment was coupled with the appearance of calmodulin-independent activity, whereas the 37/36 kDa fragment doublet remained stable. It was concluded that the 60 kDa and the 37/36 kDa fragments: (a) together represent the C-terminal two-thirds of the enzyme, which is functional as an Ca(2+)-ATPase, (b) were produced by a single cleavage near the C-terminal side of the cytosolic catalytic domain, and (c) probably remain physically and functionally associated even after cleavage has occurred. At the C-terminus, the basic calmodulin-binding domain is flanked by two highly acidic regions (domains A and B). Our results indicate that domains A and B, despite containing many Asp and Glu residues, were not readily cleaved by V8 protease, which is known to cleave selectively peptide bonds at the C-terminal side of Asp and Glu. However, if the Ca(2+)-ATPase were pre-digested with calpain I from human erythrocytes, which removed its calmodulin-binding domain (along with domain B), multiple cleavages by V8 protease in domain A were then readily observed. We propose that the calmodulin-binding domain is closely associated with the acidic domains A and B and that these acidic domains might help to co-ordinate the stimulation of the enzyme by calmodulin.

scholarly journals Modulation of erythrocyte Ca2+-ATPase by selective calpain cleavage of the calmodulin-binding domain

1989 ◽  
Vol 264 (14) ◽  
pp. 8289-8296 ◽  
Author(s):  
P James ◽  
T Vorherr ◽  
J Krebs ◽  
A Morelli ◽  
G Castello ◽  
...  
Keyword(s):  
Binding Domain ◽  
Calmodulin Binding
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