Magic Johnson's newest entertainment venture, Magic Johnson/Music/MCA Records, announced the signing this week of R&B singer Myron Avant, whose album is to be released this summer. Another division of Johnson's entertainment umbrella, Magic Johnson Music Management, announced this week it will represent Boys II Men, Kelly Price and Mase. "Magic has always been interested in popular music and never missed a concert when he didn't have a game," a spokeswoman for Magic Johnson Enterprises said. Johnson, who led the Los Angeles Lakers to five pro basketball championships in the 1980s, has helped launch movie theaters in Los Angeles, Houston and Atlanta and owns franchises of Starbucks and TGI Friday's restaurants.