The N-terminal 11 amino acids of human erythrocyte band 3 are critical for aldolase binding and protein phosphorylation: implications for band 3 function.
The 911 amino acid band 3 (SLC4A1) is the major intrinsic membrane protein of red cells and is the principal Cl-/HCO3- exchanger. The N-terminal cytoplasmic domain of band 3 anchors the spectrin-based membrane skeleton to the lipid bilayer through its interaction with ankyrin and also binds glycolytic enzymes and hemoglobin. We identified a son of a consanguineous marriage with severe anemia in association with marked deficiency of band 3 (12% +/- 4% of normal). Direct nucleotide sequencing of SLC4A1 gene demonstrated a single base substitution (T --> C) at position + 2 in the donor splice site of intron 2, resulting in the generation of a novel mutant protein. Biochemical characterization of the mutant protein showed that it lacked the first 11 N-terminal amino acids (band 3 Neapolis). The expression of the mutant protein resulted in the complete absence of membrane-bound aldolase, and the mutant band 3 could not be tyrosine phosphorylated. The ability of the malarial parasite P falciparum to invade these red cells was significantly decreased. The identification of a novel band 3 mutant and its structural and functional characterization enabled us to identify pivotal roles for the 11 N-terminal amino acids in several protein functions and, in turn, in red-cell physiology.
Perrotta
Silverio
S
Department of Pediatrics, Second University of Naples, Italy. silverio.perrotta@unina2.it
Borriello
Adriana
A
Scaloni
Andrea
A
De Franceschi
Lucia
L
Brunati
Anna Maria
AM
Turrini
Francesco
F
Nigro
Vincenzo
V
del Giudice
Emanuele Miraglia
EM
Nobili
Bruno
B
Conte
Maria Luisa
ML
Rossi
Francesca
F
Iolascon
Achille
A
Donella-Deana
Arianna
A
Zappia
Vincenzo
V
Poggi
Vincenzo
V
Anong
William
W
Low
Philip
P
Mohandas
Narla
N
Della Ragione
Fulvio
F
D000595:Amino Acid Sequence; D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004910:Erythrocyte Membrane / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004912:Erythrocytes / Q000737:chemistry / Q000378:metabolism; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006720:Homozygote; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation; D010963:Plasmodium falciparum / Q000502:physiology; D011485:Protein Binding; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics
D001457:Anion Exchange Protein 1, Erythrocyte; D012333:RNA, Messenger; D005634:Fructose-Bisphosphate Aldolase; D005947:Glucose