CK1 alpha1/1L also known as Casein Kinase 1α1/1L, CSNK1A1, CSNK1A1L, CK1 is a 337 amino acid protein that shares a high degree of sequence similarity with the alpha isoform of casein kinase 1. CK1 alpha1/1L resides in the cytoplasm and participates in the Wnt signaling pathway. By utilizing ATP within its protein kinase domain, CK1 alpha1/1L phosphorylates a large number of proteins. Enables protein serine/threonine kinase activity. Involved in several processes, including negative regulation of canonical Wnt signaling pathway; peptidyl-serine phosphorylation; and positive regulation of proteasomal ubiquitin-dependent protein catabolic process.