The alpha chain of TRAV27*01J42*01C*01/TRBV19*01J2S7*01C*02 alpha-beta T cell receptor (TR) clonotype that is specific for HLA-A*02:01-restricted M/matrix protein 1 immunodominant epitope GILGFVFTL of influenza A virus (IAV). Classified as a public TR clonotype, it is preferentially selected in effector memory CD8-positive T cells among multiple HLA-A*02:01 carriers and confers long-lived immunity against IAV infection. Can cross-recognize sporadically emerging IAV variants by molecular mimicry, inducing immunity toward different influenza strains (PubMed:1833769, PubMed:7807026, PubMed:29997621, PubMed:27036003, PubMed:12796775, PubMed:18275829). Antigen recognition initiates TR-CD3 clustering on the cell surface and intracellular activation of LCK that phosphorylates the ITAM motifs of CD3G, CD3D, CD3E and CD247 enabling the recruitment of ZAP70. In turn, ZAP70 phosphorylates LAT, which recruits numerous signaling molecules to form the LAT signalosome. The LAT signalosome propagates signal branching to three major signaling pathways, the calcium, the mitogen-activated protein kinase (MAPK) kinase and the nuclear factor NF-kappa-B (NF-kB) pathways, leading to the mobilization of transcription factors that are critical for gene expression and essential for T cell differentiation into effector/memory T cells (By similarity). Disulfide-linked heterodimer with TRBV19*01J2S7*01C*02 beta chain. The TR primarily interacts via its CDR3-beta domain with M/matrix protein 1-derived peptide (GILGFVFTL) displayed by HLA-A*02.01 in a 'peg-notch' recognition mode (PubMed:27036003, PubMed:12796775, PubMed:18275829). The alpha-beta TR associates with the transmembrane signaling CD3 coreceptor proteins to form the TR-CD3 (TCR). The assembly of alpha-beta TR heterodimers with CD3 occurs in the endoplasmic reticulum where a single alpha-beta TR heterodimer associates with one CD3D-CD3E heterodimer, one CD3G-CD3E heterodimer and one CD247 homodimer forming a stable octomeric structure. CD3D-CD3E and CD3G-CD3E heterodimers preferentially associate with TR alpha and TR beta chains (via TM domain), respectively. The association of the CD247 homodimer is the last step of TCR assembly in the endoplasmic reticulum and is required for transport to the cell surface (By similarity). Expressed in M/matrix protein 1-specific effector and memory CD8-positive T cells readily detectable in the peripheral blood, secondary lymphoid organs and lung (primary site of infection) of IAV infected individuals. The complementarity-determining region CDR1 confers specificity to the peptide antigen. Assumes a loop structure that makes contact with HLA-A*02.01 and contributes to the stability of the TR through interaction with CDR3-beta loop. The complementarity-determining region CDR2 confers specificity to the peptide antigen. Assumes a loop structure that recognizes the peptide-HLA-A*02-B2M complex. The complementarity-determining region CDR3 confers specificity to the peptide antigen. Assumes a loop structure that recognizes the peptide-HLA-A*02-B2M complex. The connecting peptide (CP) domain contributes to the TR-CD3 assembly and signal transduction. The TM domain mediates the interaction with the CD3 subunits. The JM22 clone described as a variant of the public clonotype differs by one amino acid in the CDR3-alpha domain. This sequence is an example of a full-length TR alpha chain. M/matrix protein 1-specific TRAV27*01J42*01C*01 TR alpha chain is generated by somatic recombination of variable TRAV27 (AC A0A087WT01) and joining TRAJ42 (AC A0A075B6Y9) gene segments spliced to constant TRAC (AC P01848) gene segment. Chimeric mRNA corresponding to regions V, J and C of T cell receptor (TR) alpha chain.