Catalyzes the second step in the biosynthesis of coenzyme A from vitamin B5, where cysteine is conjugated to 4'-phosphopantothenate to form 4-phosphopantothenoylcysteine (PubMed:11923312, PubMed:12906824, PubMed:29754768). Has a preference for ATP over CTP as a cosubstrate (PubMed:11923312). {ECO:0000269|PubMed:11923312, ECO:0000269|PubMed:12906824, ECO:0000269|PubMed:29754768}. This is the function of PPCS (phosphopantothenoylcysteine synthetase, ENSG00000127125).