discriminating against her on the basis of her age. Section 1983 “is not itself a source of substantive rights, but a method for vindicating federal rights elsewhere conferred by those parts of the United States Constitution and federal statutes that it describes.” Baker v. McCollan, 443 U.S. 137, 145 n. 3, 99 S.Ct. 2689, 61 L.Ed.2d 433 (1979). For claims under § 1983, a plaintiff must prove that “(1) the challenged conduct was attributable at least in part to a person who was acting under color of state law and (2) the conduct deprived the plaintiff of a right guaranteed under the Constitution of the United States.” Snider v. Dylag, 188 F.3d 51, 53 (2d Cir.1999) (citation omitted). Here, for purposes of pending cross-motions for summary judgment, the parties do not dispu (2d Cir.1989) (<HOLDING>); Shapiro v. N.Y.C. Dep’t of Educ., 561
holding that mcdonnell douglas burdenshifting approach applies to claims brought under the adea holding that adea and phra claims proceed under the mcdonnell douglas framework holding that the mcdonnell douglas framework applies equally to ada and rehabilitation act cases holding that the mcdonnell douglas burdenshifting framework applies to retaliation claims in the same manner as to discrimination claims holding that threestep analysis outlined in mcdonnell douglas applies to claims brought under  1983