Mitochondrial isoform that catalyzes the phosphorylation of pantothenate to generate 4'-phosphopantothenate in the first and rate-determining step of coenzyme A (CoA) synthesis (PubMed:15659606, PubMed:17825826, PubMed:17242360, PubMed:16272150). Required for angiogenic activity of umbilical vein of endothelial cells (HUVEC) (PubMed:30221726). Cytoplasmic isoform that catalyzes the phosphorylation of pantothenate to generate 4'-phosphopantothenate in the first and rate-determining step of coenzyme A (CoA) synthesis. (R)-pantothenate + ATP = (R)-4'-phosphopantothenate + ADP + H(+) (R)-pantothenate + ATP = (R)-4'-phosphopantothenate + ADP + H(+) Strongly inhibited by acetyl-CoA and its thioesters (PubMed:15659606, PubMed:17825826, PubMed:17242360, PubMed:16272150). Activated by palmitoylcarnitine (PubMed:17825826, PubMed:17242360). Cofactor biosynthesis; coenzyme A biosynthesis; CoA from (R)-pantothenate: step 1/5. Homodimer. Localizes predominantly to the mitochondria and to a lesser extent to the nucleus. Found in both the mitochondria and the nucleus throughout the cell cycle, with the exception of the G2/M phase when it is restricted to mitochdondria. Expressed in the brain (at protein level) (PubMed:15659606, PubMed:17825826). Ubiquitous (PubMed:11479594). Highly expressed in the testis (PubMed:17825826). Expressed in the umbilical vein endothelial cells (HUVEC) (PubMed:30221726). Synthesized as a 62-kDa precursor which is proteolytically processed by the mitochondrial-processing peptidase (MPP) via a 59-kDa intermediate to yield the mature mitochondrial 48-kDa subunit. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The HSS syndrome has been proposed to be renamed because of the unethical activities of Julius Hallervorden and Hugo Spatz during world war II. Produced by alternative initiation at Met-124 of isoform 1. May be produced by alternative initiation at Leu-111 of isoform 1. Belongs to the type II pantothenate kinase family.