The light-harvesting complex (LHC) functions as a light receptor, it captures and delivers excitation energy to photosystems with which it is closely associated (PubMed:26562806). Modulates the rate of photosystem II (PSII) state transitions and influences PSII macrostructure (PubMed:19880802). Involved in PSII excitation energy transfer and charge separation during photosynthesis in thylakoids (PubMed:26562806). Binds at least 14 chlorophylls (8 Chl-a and 6 Chl-b) and carotenoids such as lutein and neoxanthin. Present in M heterotrimers (PubMed:23274453). Forms heterotrimers with LHCB1, LHCB2, and LHCB5 proteins (PubMed:16551629, PubMed:15208324). The LHC complex consists of chlorophyll a-b binding proteins (PubMed:11245797). Repressed by high-light (HL) in a CAO-dependent manner (at protein level) (PubMed:16170635, PubMed:23598180). Reduced levels relative to CP43 during high light acclimation, thus helping photosystem II (PSII) structural re-arrangement (PubMed:23274453). Repressed by the herbicide bromacil (BRO) (PubMed:26802342). In koLhcb3, accumulation of LHCB1 and LHCB2 apoproteins to adjust photosystem II (PSII) (PubMed:19880802, PubMed:26562806). However, altered macrostructural arrangement of the LHCII antenna and increased rate of PSII transition from state 1 to state 2. Increased phosphorylation level of LHCII (PubMed:19880802). Reduced responsiveness of stomatal movement to abscisic acid (ABA), therefore resulting in a decrease in tolerance to drought stress (PubMed:22143917). Deceleration of the fast phase of excitation dynamics in grana cores (PubMed:26562806). Belongs to the light-harvesting chlorophyll a/b-binding (LHC) protein family.