Involved in defense response to Gram-positive bacterium; regulation of protein catabolic process; and regulation of transcription by RNA polymerase II. Part of mediator complex. Expressed in several structures, including P1.p; P2.p; P5.ppp; P7.paa; and vulval cell. Human ortholog(s) of this gene implicated in autosomal recessive intellectual developmental disorder 18. Is an ortholog of human MED23 (mediator complex subunit 23).