protein 4.1; Band 4.1; P4.1; EPB4.1; 4.1R (EPB41 E41P)

Introduction

band # from SDS gel of erythrocyte ghosts

Function

• major structural element of the erythrocyte membrane skeleton
• role in regulating membrane physical properties of mechanical stability & deformability by stabilizing spectrin-actin interaction
• recruits DLG1 to membranes
• phosphorylated at multiple sites by different protein kinases; each phosphorylation selectively modulates 4.1 function
• phosphorylation on Tyr-660 reduces the ability of 4.1 to promote assembly of the spectrin/actin/4.1 ternary complex
• binds with a high affinity to glycophorin & with lower affinity to band 3 protein
• associates with the nuclear mitotic apparatus
• binds calmodulin, CENPJ & DLG1
• also found to associate with contractile apparatus & tight junctions

Structure

• O-glycosylated; contains N-acetylglucosamine side chains in the C-terminal domain
• contains 1 FERM domain

Compartment

• cytoplasm, cytoskeleton. cytoplasm, cell cortex, nucleus

Alternative splicing

• named isoforms=7;
• erythroid form, non-erythroid isoforms A & B

Pathology

• abnormality results in elliptocytosis
• defects in EPB41 are the cause of
  • elliptocytosis type 1
  • hereditary pyropoikilocytosis

More general terms

• Ca+2 binding protein
• cytoskeletal protein

Database

• UniProt: http://www.uniprot.org/uniprot/P11171.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=2035
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:2035
• OMIM: https://mirror.omim.org/entry/130500
• OMIM: https://mirror.omim.org/entry/266140
• OMIM: https://mirror.omim.org/entry/611804