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Ca+2 ATPase of plasma membrane; P-type ATPase subfamily IIB (PMCA)
Function:
- high-affinity Ca+2-transporting system of plasma membranes
- only plasma membrane Ca+2-transporter in most cells, but quantitatively 2nd to low affinity Na+/Ca+2 exchanger in neurons & cardiac muscle
- PMCA serves to fine tune cytoplasmic Ca+2 with the extracellular space
- PMCA has catalytic properties of ion-motive ATPases of the P type
Compartment:
- found in plasma membranes
Alternative splicing:
- isoform diversity is enhanced by alternative splicing, with > 20 different transcripts identified
Expression:
- one erythrocyte would contain about 700 PMCA molecules
Genetics:
- product of a family of four genes located on different chromosomes
Interactions
molecular events
General
Ca+2 ATPase
calmodulin binding protein
PEST protein
plasma membrane protein
transmembrane 10 protein
Properties
COMPARTMENT: plasma membrane
CELL: erythrocyte
QUANTITY: 4.2E12-6.2E12 CELLS/UL
STATE: Active
MOTIF: cytoplasmic domain {N-TERMINAL}
exoplasmic loop
LOOP#: 1
exoplasmic loop
LOOP#: 2
exoplasmic loop
LOOP#: 3
exoplasmic loop
LOOP#: 4
exoplasmic loop
LOOP#: 5
transmembrane domain (10)
membrane region
active site
SITE: CYTOPLASMIC-LOOP-2
MOTIF: Asp phosphorylation site {D475}
ATP-binding site
NAME: ATP-binding site
SITE: K609
MOTIF: lysine residue {K609}
calmodulin binding site
SITE: CYTOPLASMIC-TAIL
FOR-BINDING-OF: calmodulin
MOTIF: Thr phosphorylation site
PEST region
cytoplasmic domain {C-TERMINAL}
References
- Wang KK et al
Calmodulin-binding proteins as calpain substrates.
Biochem J 262:693 1989
PMID: 2556106
- Carafoli E.
Biogenesis: plasma membrane calcium ATPase: 15 years of work
on the purified enzyme.
FASEB J. 1994 Oct;8(13):993-1002. Review.
PMID: 7926378