Structural protein involved in the filamentous cross-bridging between microtubules and other skeletal elements. 3 different light chains, LC1, LC2 and LC3, can associate with MAP1A and MAP1B proteins. Interacts with TIAM2. Interacts with guanylate kinase-like domain of DLG1, DLG2, DLG4. Binds to CSNK1D (By similarity). MAP1 light chain LC2: Interacts with ELAVL4 (By similarity). Brain. The basic region containing the repeats may be responsible for the binding of MAP1A to microtubules. Phosphorylated by CSNK1D. LC2 is generated from MAP1A by proteolytic processing. Belongs to the MAP1 family.