Biochemical identification of alpha-fodrin and protein 4.1 in human keratinocytes.
The mature erythrocyte has a cytoskeleton of less complexity than that of nucleated cells and has been elucidated in greater detail. Two of its major components are the heterodimeric protein spectrin and protein 4.1. We report here our isolation from human keratinocytes of immunoreactive forms of both protein 4.1 and of alpha-fodrin, the extra-erythrocytic form of alpha-spectrin. These keratinocyte proteins are approximately 125 kD and 240 kD in size, respectively. We also have isolated clones containing alpha-fodrin and protein 4.1 sequences from a human keratinocyte cDNA library. These sequences confirm the active transcription in keratinocytes of the alpha-fodrin and protein 4.1 genes. Both alpha-fodrin and protein 4.1 mRNA are detectable by Northern blot analysis in human keratinocytes, where their abundance appears not to be regulated by calcium concentration in the medium.
Mutha
S
S
Department of Dermatology, San Francisco General Hospital Medical Center, CA.
Langston
A
A
Bonifas
J M
JM
Epstein
E H
EH
D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000032:analysis* / Q000235:genetics / Q000302:isolation & purification; D003598:Cytoskeletal Proteins; D004247:DNA / Q000235:genetics; D004910:Erythrocyte Membrane; D006801:Humans; D015151:Immunoblotting; D015603:Keratinocytes / Q000737:chemistry*; D008297:Male; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics / Q000302:isolation & purification; D008840:Microfilament Proteins / Q000032:analysis* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009479:Neuropeptides; D013049:Spectrin
D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D004247:DNA; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009479:Neuropeptides; D013049:Spectrin; C028841:erythrocyte membrane band 4.1 protein; C120557:erythrocyte membrane protein band 4.1-like 1