Complex sentence: Several different laboratories initially studying the same protein, now called GAP-43, used different names, the protein was initially designated F1, then B-50, then GAP-43, pp46, and finally neuromodulin.
Split into simpler sentences: Several different laboratories initially studying the same protein, now called GAP-43, used different names. It was initially designated F1, then B-50, then GAP-43, pp46, and finally neuromodulin.