The BRAF V600E mutation, which approaches 50% in human melanomas, constitutively activates pERK and contributes to disease progression. The BRAF V600E inhibitor, Vemurafenib (PLX4032), shows promising clinical responses, but resistance to PLX4032 usually develops within a year. Transgenic mouse models allow the study of BRaf V600E melanoma in vivo, however in vitro models are necessary to better understand the molecular mechanism underlying disease progression and resistance. We established melanoma cell lines (D4M cells) from the conditional mouse model of metastatic melanoma: Tyr:: CreER; Braf CA; Pten lox/lox, which recapitulates human disease. Cultured D4M cells express high constitutive pERK. PLX4032 abrogates ERK phosphorylation, inhibits D4M proliferation, and increases expression of the melanoma associated antigen, pmel, in vitro, consistent with human BRAF V600E melanoma cell lines. D4M cells are transplantable in either immune-compromised or syngeneic B6 mice. Thus, D4M cell lines allow correlation of in vitro studies on molecular mechanisms of melanoma with in vivo investigations on pathology and immunology.