T-cell surface glycoprotein CD45 isoform RA (CD45RA)

T-cell surface glycoprotein CD45 isoform RA (CD45RA) is a major isoform of CD45, a transmembrane protein tyrosine phosphatase expressed on all hematopoietic cells, with the RA variant marking naïve T cells through inclusion of exon A in the extracellular domain[2][5]. All CD45 isoforms share an identical cytoplasmic region with intrinsic phosphatase activity, crucial for dephosphorylating the tyrosine kinase Lck as part of T-cell receptor signal transduction, thus controlling immune activation, cytokine production, and lymphocyte proliferation[1][2][3][4]. CD45 isoform diversity, generated by alternative splicing, defines lymphocyte subsets and functional states, making CD45RA a key biomarker in immunology and oncology[2][5]. The molecule is of significant interest for therapeutic strategies targeting the immune system, but isoform complexity and the broad expression of CD45 pose safety and specificity challenges[2][4][5][6].

Other names

CD45Leukocyte common antigenProtein tyrosine phosphatase receptor type C (PTPRC)CD45RA (specifically for the isoform including exon A)

Antibody-based targeting for cell depletion (experimental; pan-CD45 or isoform-specific approaches); Signal modulation through inhibition or activation of PTP function (research/experimental)