Catalyzes the attachment of alanine to tRNA(Ala) in a two-step reaction: alanine is first activated by ATP to form Ala-AMP and then transferred to the acceptor end of tRNA(Ala) (PubMed:16906134, PubMed:20010690, PubMed:25422440, PubMed:27622773). Also edits incorrectly charged tRNA(Ala) via its editing domain (PubMed:16906134, PubMed:20010690, PubMed:25422440, PubMed:29769718). ATP + L-alanine + tRNA(Ala) = AMP + diphosphate + L-alanyl-tRNA(Ala) Binds 1 zinc ion per subunit. Monomer (By similarity). Interacts with ANKRD16; the interaction is direct (PubMed:29769718). Consists of three domains; the N-terminal catalytic domain, the editing domain and the C-terminal C-Ala domain. The editing domain removes incorrectly charged amino acids, while the C-Ala domain, along with tRNA(Ala), serves as a bridge to cooperatively bring together the editing and aminoacylation centers thus stimulating deacylation of misacylated tRNAs. ISGylated. In sticky (sti); homozygous mice display an unkempt sticky appearance of fur and show cerebellar Purkinje cell loss and ataxia. Defects are caused by impaired ability to edit incorrectly charged tRNA(Ala), resulting in a two-fold increase in Ser-mischarged tRNA(Ala). This results in formation of ubiquitinated protein aggregates in cerebellar Purkinje cells and degeneration of these neurons. Was named 'sticky' because of the sticky characteristics of the fur in mice homozygous for the Glu-734 variant. Belongs to the class-II aminoacyl-tRNA synthetase family.