ATP8A1 is highly expressed in mouse platelets, but not located at the cell surface. (A) Gene expression of the P4-type ATPases and CDC50 proteins in mouse platelets. Reverse transcription polymerase chain reaction was performed using total RNA isolated from mouse platelets. CD41 and CD45 were used as positive control and negative control for the purity of platelet cDNA, respectively. (B) mRNA expression pattern of the P4-type ATPase and CDC50 genes derived from the genome-wide RNA-seq analysis of mouse platelet transcriptome.²⁰  RPKM, reads per kilobase of exon model per million mapped reads. Data were extracted from supplementary Table S4 in Rowley et al.²⁰  (C) Protein expression pattern of the P4-type ATPases and CDC50 proteins derived from the copy number analysis of murine platelet proteome.²¹  Data were extracted from supplementary Table S2 in Zeiler et al.²¹  (D) Total membrane, biotinylated surface protein, and extracted plasma membrane from mouse platelets were denatured for SDS-PAGE and then probed for ATP8A1 by western blotting. Na⁺/K⁺-ATPase was used as a marker of plasma membrane protein. Immunoblots are representative of 3 independent experiments. (E) Expression of ATP11C in platelets and liver from Atp11c^+/0 (wild-type) and Atp11c^amb/0 (ambrosius) mice. Mouse platelet cell lysates and liver tissue homogenates were denatured for SDS-PAGE and then probed for ATP11C through western blot. *Nonspecific bands. Immunoblots are representative of 3 independent experiments.