RNA recognition motif 2 (RRM2) found in Limkain-b1 (LKAP) and similar proteins
This subfamily corresponds to the RRM2 of LKAP, a novel peroxisomal autoantigen that co-localizes with a subset of cytoplasmic microbodies marked by ABCD3 (ATP-binding cassette subfamily D member 3, known previously as PMP-70) and/or PXF (peroxisomal farnesylated protein, known previously as PEX19). It associates with LIM kinase 2 (LIMK2) and may serve as a relatively common target of human autoantibodies reactive to cytoplasmic vesicle-like structures. LKAP contains two RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). However, whether those RRMs are bona fide RNA binding sites remains unclear. Moreover, there is no evidence of LAKP localization in the nucleus. Therefore, if the RRMs are functional, their interaction with RNA species would be restricted to the cytoplasm and peroxisomes.